Syria conflict: World powers to intensify quest for peace
Allies and opponents of Syrian President Bashar al-Assad have agreed to renew efforts to end the civil war.
The Vienna talks involved Iran, a key Assad ally, for the first time.
The ministers agreed to ask the United Nations to start a process that could lead to a ceasefire and new elections. But they disagreed over Mr Assad's future. New talks are due in two weeks.
Ahead of the talks, a Syrian government attack on a Damascus suburb left at least 57 people dead.
The Vienna meeting sought to close the gap between the United States and its allies, who support the rebels, and the key foreign allies of the Syrian government, Russia and Iran.
After nearly eight hours of talks, the ministers agreed on a number of points, including:
- inviting the UN to convene Syria's government and opposition to launch a new political process that is "credible, inclusive, non-sectarian"
- a new constitution and UN-backed elections that involve all Syrians, including members of the diaspora and of all ethnicities
- improved access to humanitarian aid for Syrians in and outside the country
- working with the UN to "explore modalities for, and implementation of, a nationwide ceasefire"
The four-year-old war in Syria, which began with an uprising against President Assad, has left 250,000 people dead and forced half the country's population - or 11 million people - from their homes.
Russia and Iran have recently stepped up their military involvement in the conflict, backing forces loyal to Mr Assad.
But the US, Turkey, Saudi Arabia and other Gulf Arab nations have long insisted that Mr Assad cannot play a long-term role in Syria's future.
"Four-and-a-half years of war, we all believe, has been far too long," US Secretary of State John Kerry said.
"The time has come to stop the bleeding and start the building."
Mr Kerry and his Russian counterpart Sergei Lavrov said they continued to disagree on the fate of Mr Assad.
While the US says Mr Assad should have no role in Syria's future, Mr Lavrov said: "The Syrian people should decide Assad's fate." He added that he "did not say that Assad has to go or that Assad has to stay".
Staffan de Mistura, the UN's envoy to Syria, said it was "unimaginable" even a few weeks ago that all parties would have agreed to talks, but added that much work and compromise remained to be done.
Where key players stand on Assad
- US: Assad must go, but does not need to happen before a political transition process get under way
- Saudi Arabia: Assad must go "within a specific timeframe" and before any elections for a new government
- Turkey: Assad must go, though could remain for a "symbolic" six months
- SNC (main Western- and Gulf Arab-backed anti-Assad opposition): Assad must go, cannot be part of any political process
- Russia: Assad should not be forced to go, Syrians should hold elections to decide who rules them
- Iran: Assad should not step down, Syrians should decide their own political future
The UK-based Syrian Observatory for Human Rights said at least 100 people were wounded in what it said was a Syrian government air raid in Douma.
At least five children were among the 57 dead, the group reported.
Footage uploaded to the internet - which cannot be independently verified - showed bodies strewn across the ruins of a marketplace in the rebel-held suburb of Douma on Friday morning.
The area is often targeted by the government, and rebels fire rockets from there into Damascus.
The Syrian Observatory for Human Rights said at least 12 rockets were fired at Douma.
Meanwhile, a US official told the BBC that the Obama administration is preparing to send "fewer than 50" special forces troops to Syria.
The troops will advise rebels supported by Washington in the fight against Islamist State (IS) militants, the White House said.
Russia began its military intervention in Syria at the end of last month, launching air strikes in support of Mr Assad and said on Friday it had hit 1,600 targets in the last month, including 51 training camps.
Analysis: Bethany Bell, BBC News, Vienna
No-one at the talks in Vienna is under any illusions as to the challenges that lie ahead.
Every attempt in the past to solve the Syrian conflict through diplomacy has failed. But there is a new sense of momentum, a new willingness to co-operate.
The atmosphere between Mr Kerry and Mr Lavrov at the final press conference was cordial.
There was no agreement on the fate of the Syrian President Bashar al-Assad. The United States and its allies, including Saudi Arabia toned down their calls for him to be swiftly removed from power. Russia and Iran did not specifically rule out his eventual departure.
However, many details remain vague. It's not clear when - or even if - the Syrian government or the rebels groups will join in the process.