Back in April, in the immediate aftermath of the US cruise missile attack on Syria’s Al-Shayrat air base, Russia retaliated by switching off the ‘de-confliction’ hotline between the US and Russian militaries in Syria, which enables these militaries to avoid accidental clashes with each other.

Russia is well known worldwide for its advanced aerospace capabilities and war aviation.

That this was the case was confirmed by an article in The New York Times dated 8th April 2017, which said the following

The American-led task force that is battling the Islamic State has sharply reduced airstrikes against the militants in Syria as commanders assess whether Syrian government forces or their Russian allies plan to respond to the United States’ cruise missile strike on a Syrian airfield this past week, American officials said.

The precautionary move, revealed in statistics made public by the command on Saturday, was taken as Russian officials have threatened to suspend the communication line the American and Russian militaries use to notify each other about air operations in Syria.

So far, the Russian military does not appear to have taken any threatening actions, such as directing its battlefield radar or air defense systems to confront the Americans, or carrying out aggressive actions in the skies, United States officials said.

But officials who spoke on the condition of anonymity to discuss internal planning said the commanders needed time to determine whether the Syrian president, Bashar al-Assad, and the Russian military would treat the American cruise missile strike as a one-time operation that they would not respond to militarily. As a precaution, the Pentagon is flying patrols in Syrian skies with F-22 jets, the Air Force’s most advanced air-to-air fighter……

Some American and other Western counterterrorism officials have said the missile strike could………make the fight against the Islamic State in Syria more difficult.

“It seems clear that the strikes will complicate our efforts to pursue our counter-ISIS campaign in Syria,” said Matthew Olsen, a former director of the National Counterterrorism Center. “In particular, the ability to carry out U.S. airstrikes in Syria in support of the coalition against ISIS requires some degree of cooperation with Russia, which is now in serious jeopardy.”

Other security experts said that much depended on the Trump administration’s next steps, and how the Assad government and its Russian patrons responded.

“U.S. aircraft operating over Al-Tabqah are already ostensibly in range of the Russian S-400 system at the Humaymin Air Base, and we might see Russia deploy more air defense assets to Syria,” Jeremy Binnie, the Middle East editor of Jane’s Defense Weekly, said in an email. “But if the U.S. makes no moves to threaten Assad’s position, then they may well accept the punishment and move on.”

William McCants, a senior fellow at the Brookings Institution and the author of “The ISIS Apocalypse,” offered a similar assessment.

(bold italics added)

S-400 battery in field exercises. The most advanced anti-aircraft system in the world. A game-changer. The challenge for Russia is to produce it in sufficient quantities as to make it a general deterrent against Western aggression.

The words I have highlighted in this article from 8th April 2017 make clear the difference with the situation today.

After weeks of frantic diplomatic activity the US finally managed to persuade the Russians a few weeks ago to switch the ‘de-confliction’ hotline back on.  In response to yesterday’s US shooting down of the SU-22 the Russians have however now once again switched it off.

However this time the Russians have not only once more switched off the ‘de-confliction’ hotline.  They have also done what they did not do in April by saying that this time they will take “threatening action by directing their battlefield radar or air defense systems to confront the Americans”.

That this is so is explicitly confirmed in the statement made public yesterday by the Russian Defence Ministry

As of June 19 this year, the Defense Ministry of the Russian Federation has ended its interaction with the US side under a memorandum for preventing incidents and providing for safe flights during operations in Syria and demands that the US command carry out a careful investigation and report about its results and the measures taken.

The shooting down of a Syrian Air Force jet in Syria’s airspace is a cynical violation of Syria’s sovereignty. The US’ repeated combat operations under the guise of ‘combating terrorism’ against the legitimate armed forces of a UN member-state are a flagrant violation of international law, in addition to being actual military aggression against the Syrian Arab Republic,” the ministry said.

Russia will regard any flights within the area of its air force group’s operation in Syria as legitimate targets, the ministry stressed.

Any aircraft, including planes and drones of the international coalition, detected in the operation areas west of the Euphrates River by the Russian air forces will be followed by Russian ground-based air defense and air defense aircraft as air targets.

…….the coalition command did not use the existing communication line between the air commands of Al Udeid Air Base (Qatar) and Khmeimim Air Base to prevent incidents in Syria’s airspace.  We consider the actions of the US command as a deliberate default on their obligations under the memorandum on on preventing incidents and providing for safe flights during operations in Syria signed on October 20, 2015.

(bold italics added)

Alexander-Dvornikov-C-in-C of the Russian-Syrian Task-Force

In other words, the Russian response to the shooting down of the Syrian SU-22 fighter near Taqbah has been much stronger than was the Russian response to the US cruise missile attack on Syria’s Al-Shayrat air base.

This is so even though the attack on Al-Shayrat air base attracted massive international media attention, whilst the US shooting down of the SU-22 has attracted very little.

This time however the Russians have announced that they will do precisely the thing which they did not do in April following the US attack on Al-Shayrat air base – and which the New York Times says is very threatening – which is track US aircraft, treating them as targets if they fly west of the Euphrates.

Why have the Russians taken this extraordinary step?

The US claims yesterday justifying the shooting down of the SU-22 aircraft have unravelled.  Even the strongly anti-Assad British based Syrian Observatory of Human Rights has confirmed that the SU-22 was not bombing Kurdish forces as the US claims but was bombing ISIS fighters as the Syrians say.

A regime warplane was targeted and dropped in the skies of the al-Resafa area […] the warplane was shot down over Al-Resafa area of which the regime forces have reached to its frontiers today, and sources suggested to the Syrian Observatory for Human Rights that warplanes of the International Coalition targeted it during its flight in close proximity to the airspace of the International Coalition’s warplanes, which caused its debris to fall over Resafa city amid an unknown fate of its pilot, the sources confirmed that the warplane did not target the Syria Democratic Forces in their controlled areas located at the contact line with regime forces’ controlled areas in the western countryside of Al-Tabaqa to the road of Al-Raqqah – Resafa.

(bold italics added)

Another thing that may have provoked the Russians is that the US has tried to pass off the downing of the SU-22 as caused by Syrian encroachment of an agreed ‘de-confliction area’.

Ja’Din sits approximately two kilometers north of an established East-West SDF-Syrian Regime de-confliction area.

This uses a term – ‘de-confliction area’ – used to describe certain regions of Syria covered by an international agreement reached by Russia, Iran and Turkey in May.

The area where the SU-22 was shot down is not within any of these regions.  Al-Jazeera has provided details of where these four ‘de-confliction areas’, and none of them is close to the territory where the SU-22 was shot down

Zone 1 : Idlib province, as well as northeastern areas of Latakia province, western areas of Aleppo province and northern areas of Hama province. There are more than one million civilians in this zone and its rebel factions are dominated by an al-Qaeda -linked alliance.

– Zone 2: The Rastan and Talbiseh enclave in northern Homs province. There are approximately 180,000 civilians in this zone and its network of rebel groups includes al-Qaeda-linked fighters.

– Zone 3 : Eastern Ghouta in the northern Damascus countryside. Controlled by Jaish al-Islam, a powerful rebel faction that is participating in the Astana talks. It is home to about 690,000 civilians. This zone does not include the adjacent, government-besieged area of Qaboun.

– Zone 4 : The rebel-controlled south along the border with Jordan that includes parts of Deraa and Quneitra provinces. Up to 800,000 civilians live there.

Whilst it is possible that the term “established East-West SDF-Syrian Regime de-confliction area” refers to a term used in some informal agreement between the US and Russia, it seems more likely that the US is trying to establish unilaterally ‘no-go’ areas for the Syrian army, and is using the term ‘de-escalation areas’ to conceal the fact.

If so the Russians will want to put a stop to this practice and this may partly explain the strength of the Russian reaction.

However the single most important reason for the strong Russian reaction is what caused the US to shoot down the SU-22 down in the first place.

As the report from the Syrian Observatory of Human Rights shows, the real reason the SU-22 was shot down was because it was supporting a Syrian army offensive to capture the strategically important town of Rusafa from ISIS.

Rusafa lies south east of Tabqah – the main base of the US backed Kurdish militia in this area – and within striking distance of the main highway between Raqqa and Deir Ezzor, the eastern desert city currently besieged by ISIS.

By capturing Rusafa the Syrian army is now in a position to intercept columns of ISIS fighters who might try to flee Raqqa for Deir Ezzor.

The Syrians and the Russians have in recent weeks complained that the US and the Kurds have been doing nothing to prevent ISIS fighters fleeing Raqqa for Deir Ezzor, and in recent days there have even been reports of movements by Kurdish militia to try to block the Syrian army’s offensive to relieve Deir Ezzor.

The shooting down of the Syrian SU-22 fighter appears to have been intended as a warning to stop the Syrian army from capturing Rusafa, so as to block the Syrian army’s attempt to relieve the pressure on Deir Ezzor.

The Russian warning to the US looks in turn to have been intended to make clear to the US that this sort of interference in the Syrian army’s operations to relieve Deir Ezzor is unacceptable and will not be tolerated.

The US has heeded the Russian warning.  The various statements made by the US and by various US officials today, though full of the usual bluster about the US defending itself and its allies anywhere and everywhere, in fact clearly signal that the US is backing off.

The key words – as my colleague Adam Garrie has said – are those of Colonel Ryan Dillon, chief U.S. military spokesman in Baghdad.

As a result of recent encounters involving pro-Syrian regime and Russian forces, we have taken prudent measures to reposition aircraft over Syria so as to continue targeting ISIS forces while ensuring the safety of our aircrews given known threats in the battle space.

(bold italics added)

“Prudent measures to reposition aircraft over Syria to ensure the safety of aircrews given known threats in the battle space” is code for withdrawal of aircraft from air space where they are at risk of being shot down.

That is what is taking place.  Note that Colonel Dillon is careful not to say where the “known threats in the battle space” that are forcing the redeployment of the aircraft are coming from.

The US has no choice.  If the Russian decision to switch off the ‘de-confliction’ hotline in April was enough to force the US to reduce sharply its air activity in Syria, the Russian decision to switch off the ‘de-confliction’ hotline and to threaten to treat as aerial targets US aircraft flying west of the Euphrates is a threat the US cannot afford to disregard.

Not surprisingly, shortly before the Russian warning was made public, but probably after it was communicated to the US, the Syrian army captured Rusafa with no further hindrance from the US.  Latest reports speak of Syrian army reinforcements flooding into the area,

In the meantime the US is frantically signalling to the Russians its urgent wish to de-escalate the situation.  Note for example the markedly conciliatory language of White House spokesman Sean Spicer, and how he repeatedly passed up opportunities to utter words of defiance against Russia or to threaten the Russians with counter-measures during the latest White House press briefing

Q    Thanks, Sean.  How are you responding to this Russian threat to shoot down American planes over Syria?

MR. SPICER:  Well, obviously, we’re going to do what we can to protect our interests.  And this is something that we’re going to continue to work with — keep the lines of communication open.   And ISIS represents a threat to all nations, and so we’ve got to do what we can to work with partners.  And we’re going to continue to keep an open mind of communication with the Russians.

Q    So will the U.S. change its flight patterns or behavior in Syria?

MR. SPICER:  I’m going to refer — I mean, I think this is a question more for DOD to answer.  But I think, obviously, it’s important and crucial that we keep lines of communication open to de-conflict potential issues.

Zeke.

Q    Thanks, Sean.  Following up on that — and a second one for you, as well — what would the U.S. government’s response be?  Is the White House going to issue a warning to the Russian government if they were to follow through on this threat?  It seems that your statement — would that be a provocation or something worse, potentially?

MR. SPICER:  I mean, I think that the escalation of hostilities among the many factions that are operating in this region doesn’t help anybody.  And the Syrian regime and others in the regime need to understand that we will retain the right of self-defense, of coalition forces aligned against ISIS.

Ultimately the situation in Syria is the same as it has been since the US-Russian confrontation in October.

The fact that the Russians have installed a powerful air defence system in Syria incorporating advanced S-400 and S-300VM Antey 2500 missiles means that the US is unable to confront the Russians directly unless it is prepared to risk possibly very serious casualties.

That is an option neither the US military nor the civilian officials of the Obama and Trump administrations are prepared to face.  This is because they know the extraordinary dangers such a clash with the armed forces of a nuclear superpower would risk.  They also know US public opinion is strongly opposed to the US becoming drawn into such a clash.

What that means is that though the Russians must act carefully so as not to provoke the US into an unnecessary confrontation which would serve no-one’s interests, ultimately it is the Russians who in Syria have the whip hand.

The chess game in Syria is far from over.  The game of move and counter-move continues.  With the capture of Rusafa the Syrians and the Russians have however just won another important piece.  In the meantime Russia’s warning limits the range of US moves across the Syrian chessboard.

The net result of all these recent moves is that end of the Syrian war may have drawn a little closer.