The leaders of Britain and Russia have met in London for talks expected to be overshadowed by their disagreements over Syria.
British Prime Minister David Cameron wants to help the Syrian opposition and has accused the government of President Bashar al Assad of using chemical weapons.
But the BBC reports President Vladimir Putin is deeply sceptical about the accusations.
Mr Cameron said they would be discussing the need to get movement on an international deal for peace in Syria.
Earlier, he said no decision had been made in Britain to follow the United States in arming Syrian rebels.
Mr Putin was late arriving at Downing Street on Sunday due to an unrelated demonstration in Whitehall.
Mr Cameron told Sky News that everyone wanted to see movement on a peace conference on Syria, leading to a transitional government, but the disagreement was about "how we get there".
On Friday, the United States announced it would supply some rebels with direct military aid.
The G8 summit begins in Lough Erne, County Fermanagh in Northern Ireland on Monday and Tuesday.
Canada, France, Germany, Italy, Japan, Russia, the US and Britain will be represented.
Mr Cameron will also meet US President Barack Obama ahead of the summit.