Barack Obama and Vladimir Putin held what the US president described as a “candid, blunt and businesslike” meeting on the sidelines of the G20 summit in Hangzhou, China, on Monday.

Photographs suggested that the exchange between two of the most powerful men in the world had been frosty, and Mr Obama said afterwards that "gaps of trust" between the rival powers had hindered negotiations.

Mr Obama said he had not given up on a US-Russian military partnership on Syria to tackle Isil, but that there had been no breakthrough on finding common ground.