David Cameron and Vladimir Putin discuss Syria 'differences'
Both the UK and Russia want to see an end to the violence in Syria, David Cameron has said after holding talks with Vladimir Putin in London.
Mr Cameron said he and the Russian president had "differences" over their approach but both wanted an end to the conflict and a "stable Syria".
The two men also discussed trade and security issues on Mr Putin's first trip to Britain for seven years.
They travelled afterwards to the Olympics to watch the judo competition.
BBC Political Correspondent Carole Walker said Downing Street described the 45-minute conversation as "open and frank" with clear differences expressed over Syria.
The UK has condemned attacks by the Syrian army and state-backed militia on opposition-held areas as the government seeks to regain full control of the country's biggest city, Aleppo.
The UK has long called for President Bashar-al Assad to stand down but Russia opposes foreign intervention on either side in the conflict.
Russia and China vetoed the latest UN attempt to end the fighting and Russia's foreign ministry said on Thursday it would not endorse a UN General Assembly resolution on Syria calling for a political transition - saying it was "one-sided and unbalanced" against the Syrian government.
Mr Cameron told reporters: "While of course we have had some differences in the position we have taken over the conflict we both want to see an end to that conflict and a stable Syria."
'Eye to eye'
In response, Mr Putin said the UK and Russia saw "eye-to-eye" on aspects of the situation in Syria and would work together to find a "viable solution".
Minutes after the two concluded their meeting, the UN's envoy to Syria Kofi Annan - who has sought to broker a ceasefire - announced he would be stepping down in August.
The Russian leader was last in Britain for the Gleneagles G8 summit in July 2005, since when Anglo-Russian relations have been beset by tensions over the murder of former KGB agent Alexander Litvinenko, concern about human rights in Russia and disagreements over the Middle East.
But Mr Cameron said there were many areas where the two countries could work together, including trade, energy and security, and Thursday's meeting was aimed at a "further strengthening" of relations between the two countries.
Mr Putin, who is a black belt and former St Petersburg judo champion, will meet Russian athletes competing in the Olympics and watch a number of bouts in the judo competition.
The Russian president praised London 2012's Opening Ceremony, which he chose not to attend in person, as "wonderful and unforgettable".
"It was a wonderful feast presented by you to mankind," he said.
The two discussed new areas for increasing mutual trade, which President Putin said had grown by 35/40% last year.
Ahead of his visit, British musicians have appealed to Russian authorities to give punk rock group Pussy Riot - due to stand trial for performing a protest song in Moscow - a "fair hearing".
In a letter to the Times, artists including Jarvis Cocker, Pete Townshend, Martha Wainwright and Neil Tennant, said the possibility of a seven-year jail sentence for the three women in the group was "entirely disproportionate" for what was a "minor breach of the peace".