The civil war in Syria is not on the official agenda for the G20 Summit, which begins Thursday (05.09.2013) in St. Petersburg, however it's likely to dominate proceedings. Russian President Vladimir Putin, as the summit's host, has said a military strike against Syria would break international law, however, in an interview he said Russia would consider a military intervention if there was "convincing" evidence presented at the United Nations Security Council that the Syrian government used chemical weapons against rebels.

Putin added that Russia would not get involved in a mission targeting Syrian forces without a UN mandate saying, "According to international law, only the UN Security Council can give approval for the use of force against another state." Any other course of action, he said, would be "unacceptable" and could be seen as an act of aggression.

A long-time ally of Syrian President Bashar al-Assad, Russia has used its veto in the UN Security Council to prevent resolutions condemning violence in Syria.

DW talked to Sabine Fischer who heads the Eastern Europe, Eurasia Research Division at the German Institute for International and Security Affairs.

DW: Is Putin turning his back on Assad?

Sabine Fischer: Over the past two years there have been moments when you got the feeling that the Russian leadership was trying to distance itself slightly from the Syrian regime and putting out feelers on a possible agreement with Western states. It is a signal to the United States and its allies that Russia is ready for negotiations. It is, of course, tied to the G20 Summit, where Putin and Obama will cross paths.

How serious is Putin when he says he would support a military intervention?

Putin's statement still leaves a number of doors open for the Russian leadership. Putin placed conditions, including very clear evidence that the Syrian regime used chemical weapons, on what it would take for the Russian government potentially to support a military intervention,.

The Russian leadership is in a difficult position. Russia has continually supported the Assad regime for the last two years. It has very concrete interests in the region that are tied to Syria. On the other hand, because of its actions Russia has seen itself increasing isolated by the international community.

On the international stage, Russia in recent years has very strongly insisted on maintaining international law. If the Syrian regime indeed broke international law in such a brutal way by allegedly using poison gas then the Russian leadership would be in a very uncomfortable position. Moscow would have to deviate from its course of support for the Syrian leadership. I think that was one of the reasons Putin opened the door with his statement.

What could the West do to pull Russia on its side?

It is absolutely essential that the West, and particularly the American president, use the G20 Summit as a means of engaging Russia. Obama also gave himself a 10-day window to let diplomacy work with his decision to seek congressional approval for a military attack.

But for Russia to agree to a military attack, a UN commission will have to deliver proof that chemical weapons were used as well as evidence that they were actually used by the Syrian regime.

How important is Russia to Syria?

Russia is of course an important economic partner for Syria. It delivers weapons and supports Syria on the international stage. At the same time, it has also become clear that the Syrian regime is mainly following its own interests as the civil war continues and that no thought was given to the Russian position in regards to the possible use of chemical weapons.

Russia does not control this regime and Russia is in a difficult position because of actions taken by the Assad regime.

Assuming that Russia stops supporting the Syrian government, would that spell the end of the Assad regime?

I don't think that a change in the Russian position would end the war. The regime has its back up against the wall and is fighting for survival. It has its own momentum, which Russia also cannot influence.