US President Barack Obama told the BBC that any Western attempt to overthrow the regime of Syrian President Bashar al-Assad using ground troops would be a mistake, but international pressure on his allies could help bring about a settlement.
"It would be a mistake for the United States or Great Britain or a combination of Western states to send in ground troops and overthrow the Assad regime," Obama told the British state broadcaster in an interview.
International pressure on al-Assad's key backers, Russia and Iran, as well as on moderate Syrian rebels, could instead bring them to the negotiating table to "try and broker a transition," he said.
The Syrian opposition last week said it had asked the UN to put peace talks in Geneva - officially backed by Russia and Iran as well as the US - on hold in response to breaches of a shaky ceasefire by government forces.
The BBC released excerpts of the interview on Sunday as the US president, whose second and last term of office ends in January, travelled from Britain to Germany in what is expected to be his last major international tour.
Obama has consistently been sceptical about the merits of intervention in Syria's five-year-long civil war, despite calls from Turkey and Gulf allies for more support for rebels fighting al-Assad and the Islamic State extremist group.
The US has reportedly provided limited covert support to Syrian rebels, and a contingent of about 50 US special forces was sent to Syria late last year to assist Kurdish-led forces in their ground offensive against Islamic State in northern Syria.
The BBC quoted Obama as saying that he did not think the Islamic State extremist group would be defeated in the remaining nine months of his presidency.
But the US would still target its strongholds such as the north-eastern Syrian city of al-Raqqa and would "try to isolate those portions of the country, and lock down those portions of the country that are sending foreign fighters into Europe," the president said.
Syria's civil war, which started in 2011 after al-Assad's forces launched a brutal crackdown against protests, has cost a quarter of a million lives and displaced half the country's population, according to UN estimates.