Barack Obama and Vladimir Putin seek Syria peace
US President Barack Obama and Russian President Vladimir Putin have urged an immediate end to violence in Syria.
In a joint statement following their first meeting since Mr Putin returned to the presidency, they said they shared a belief that Syrians should determine their own future.
The two countries have been at odds over how to resolve the crisis.
Russia and China have twice blocked US-backed UN draft resolutions critical of Syria.
Both countries argue that pushing the government from power using external pressure is unacceptable.
The meeting of the two leaders on the sidelines of the G20 summit in Los Cabos, Mexico, came amid unconfirmed reports that Russian ships were preparing to set sail for Syria.
The Russian news agency Interfax quoted a navy source as saying the ship Kaliningrad, part of the Baltic Fleet, was preparing for a trip in the Mediterranean, as part of which "the ship will visit the Syrian port of Tartus, where the Russian navy's logistics station is located".
The report comes a day after Interfax reported that two amphibious vessels were apparently on a mission to protect Russian citizens and remove equipment if necessary from the naval base in Tartus.
BBC defence correspondent Jonathan Marcus says that, if confirmed, the deployment of the ships suggests the Russians are taking prudent precautions in the event of the Syrian regime collapsing.
Also on Tuesday, British marine insurance company Standard Club said it had withdrawn insurance from a Russian ship, the MV Alaed, because of the possibility it was carrying weapons to Syria.
"We were made aware of the allegations that the Alaed was carrying munitions destined for Syria. We have informed the ship owner that their cover ceased automatically in view of the nature of their voyage," the company said in a statement.
Last week, US Secretary of State Hillary Clinton accused Russia of supplying Syria with attack helicopters, saying this would escalate the conflict "quite dramatically".
However, on Tuesday, President Putin's spokesman Dmitry Peskov denied this, telling reporters: "Russia is not selling or delivering helicopters to Syria."
Russian specialists were only maintaining helicopters that were sold to Damascus "a very long time ago", Mr Peskov said.
Meanwhile, at least 71 people were killed in the latest violence across Syria on Monday, according to the UK-based Syrian Observatory for Human Rights.
Intense artillery fire was reported by activists in several areas, including the cities of Homs and Deir Ezzor and the Damascus suburbs of Douma and Qudsiya.
On Tuesday, the Syrian government said it was willing to facilitate the evacuation of hundreds of civilians reportedly trapped by fighting in Homs.
The head of UN observers in Syria, Maj Gen Robert Mood, had earlier admitted "attempts to extract civilians" from the besieged city of Homs over the past week had been unsuccessful and urged warring parties to let them leave.
The government was willing "to extract the citizens... without any preconditions", but "armed terrorist groups' obstructions" meant this had not happened, the Syrian foreign ministry told state-run news agency Sana.
Speaking after the two-hour meeting, Mr Obama said he and Mr Putin had pledged to work with "other international actors, including the United Nations, Kofi Annan, and all interested parties" to try to find a solution to the Syria crisis.
Mr Putin said the two countries had found "many common points" on Syria.
The US and Russian leaders also warned Iran to comply fully with its international obligations over its controversial nuclear programme, calling for the "minimisation of the civilian use of highly enriched uranium".
And on the issue of missile defence, the two sides said they would work to resolve a dispute over US plans to deploy a shield in Europe.
Correspondents say there were no smiles between Mr Obama and Mr Putin during the news conference, and their interactions seemed stiff and strained.