Barack Obama and Vladimir Putin Go Head-to-Head at G20

Putin added that Russian Federation was ready to “closely cooperate” with France in its investigation of the attacks.

US President Barack Obama and Vladimir Putin of Russian Federation huddled Sunday for a coffee-table summit, breaking the ice for the first time since Moscow launched air bombardments in Syria.

In the immediate aftermath of the attacks, the Kremlin offered its condolences, condemning the “hateful” string of attacks and “inhuman murders”.

The Russian president told Mr Cameron: “The latest tragic events in Paris show that we have to unite our efforts in fighting this evil, something we should have done a long time ago”.

Obama and Putin nevertheless agreed on the need for United Nations talks, a ceasefire and a transition government in Syria, the USA official said, seeking a way out of a four-year war in which IS jihadists have thrived, occupying large swathes of territory and displacing millions of people.

“We are realistic… There is a lot still to be worked out”, the source said.

The United States and the FSA itself have both accused the Kremlin of bombing FSA targets, while largely sparing Islamic State in Iraq and the Levant (ISIL) targets.

Speaking ahead of today’s meeting, Mr Cameron said: “It’s become even more clear that our safety and security depends on degrading and ultimately destroying Isil whether it’s in Iraq or Syria”.

Mr Cameron will also urge Mr Putin, from a humanitarian point of view, to put pressure on the Assad regime to stop using barrel bombs against its citizens – something which is believed to have driven a recent surge in refugees fleeing the country.

“I think people want to know that there is a whole plan for the future of Syria, the future of the region, because it is perfectly right to say that a few extra bombs and missiles won’t transform the situation. My argument is those plans are there – t hey need to be set out more clearly and more explanation given”.

A communique agreed by the leaders condemned the IS atrocities as “an unacceptable affront to all humanity” and resolved “to prevent and suppress terrorist acts through increased global solidarity and co-operation”.

The PM hopes to revive the spirit of lengthy discussions at a 2012 meeting at Putin’s dacha in Sochi, when the two men were able to have “deeper” conversations about Syria’s future.

Obama, Cameron, Italian Prime Minister Matteo Renzi, German Chancellor Angela Merkel and French Foreign Minister Laurent Fabius will meet on Monday afternoon to discuss tackling ISIL and making a coordinated effort on the political process in Syria.

Putin reportedly thanked Cameron for sharing British intelligence suggesting Daesh may have bombed a Russian airliner that crashed shortly after taking off from the Egyptian resort of Sharm el-Sheikh last month.