British Prime Minister David Cameron said Monday his priority at the G8 summit was to ensure a peace conference on the Syrian conflict takes place later this year to push through a transitional government to replace President Bashar al-Assad.
As Western powers move increasingly to arm the rebels, Cameron said he was "as worried as anybody else" about extremist elements in the Syrian opposition.
But in a round of TV interviews hours before the summit begins, Cameron said: "We (Britain) haven't made a decision to give any arms to the Syrian opposition but what we do need to do is bring about this peace conference and this transition, so that people in Syria can have a government that represents them, rather than a government that's trying to butcher them.
"What we are doing right now is helping the official Syrian opposition -- people who have signed up to democracy and human rights, who want that sort of future for Syria."
Cameron said Assad "wants us to think that the only alternative to him is extremism and violence".
"Yet there are millions of people in Syria who want a peaceful and democratic future. We should be on their side."
He added: "Let's be clear. I am as worried as anybody else about elements of the Syrian opposition, who are extremists, who support terrorism and who are a great danger to our world.
"My argument is that we shouldn't accept that the only alternative to Assad is terrorism and violence."
Cameron said Assad was using chemical weapons against his own people -- an assessment rejected by Russian President Vladimir Putin.
"What we can try and do here at the G8 is have further pressure for the peace conference and the transition that is needed to bring this conflict to an end," the British premier said.
A first peace conference on Syria took place in Geneva in June last year and a second was mooted for this month, but it appears it will not take place until July at the earliest.
Cameron will host Putin, US President Barack Obama, German Chancellor Angela Merkel, French President Francois Hollande, Japanese Prime Minister Shinzo Abe, Italian Prime Minister Enrico Letta and Canadian Prime Minister Stephen Harper at the summit.