President Barack Obama sat down with Russian President Vladimir Putin for crucial talks on the sidelines of the G20 summit as both countries pledged to eliminate ISIS and end the Syrian war that has fueled its rise.

Their huddle over a coffee table in Antalya, Turkey, on Sunday came after the extremist group claimed responsibility for Friday's horrific coordinated attacks in Paris that left 129 people dead and hundreds injured.

The two leaders, who saw each other for the first time since Russia started air strikes over Syria in September, chatted in a foursome with Obama's national security adviser Susan Rice and a Russian aide.

Their meeting was visible on a television feed provided by the summit's host country but their conversation could not be heard.

The White House says the 35-minute encounter centered on talks to end Syria's civil war and that the two leaders agreed that the country needs a political transition led by Syrians. The transition would be preceded by negotiations mediated by the United Nations and a cease-fire.

The two leaders also discussed the conflict in Ukraine and Obama expressed condolences for the victims in the Russian plane crash in the Sinai Peninsula last month.