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 two Russian ships were preparing to set sail for Syria.
The two amphibious vessels are 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 that the Russians are taking prudent precautions in the event of the Syrian regime collapsing.
Meanwhile at least 52 people were killed in the latest violence across Syria, activists said.
Intense artillery fire was reported in several areas, including the cities of Homs and Deir Ezzor and the Damascus suburb of Douma.
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.
"In order to stop the bloodshed in Syria, we call for an immediate cessation of all violence," the leaders said in a joint statement.
"We are united in the belief that the Syrian people should have the opportunity to independently and democratically choose their own future."
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.