Russian Foreign Minister Sergei Lavrov and US Secretary of State John Kerry
The US-Russia deal on Syria's chemical weapons is a "victory" that averts war, a Syrian minister says.
The framework document says Syria must provide full details of its stockpile within a week - with the chemical arsenal eliminated by mid-2014.
If Syria fails to comply, the deal could be enforced by a UN resolution with the use of force as a last resort.
The US had threatened to attack Syria which it blames for a chemical attack in August which killed hundreds.
President Bashar al-Assad's government denies the allegations and has accused the rebels of carrying out the attack.
Syria recently agreed to join the global Chemical Weapons Convention, and the UN said it would come under the treaty from 14 October.
The framework deal was announced on Saturday after three days of talks in Geneva by Russian Foreign Minister Sergei Lavrov and US Secretary of State John Kerry.
"We welcome the agreement," Syrian Reconciliation Minister Ali Haidar told Russian news agency Ria Novosti, giving his country's first reaction.
"On the one hand, it helps Syria come out of the crisis and, on the other, it helps avoid the war against Syria depriving those who wanted to launch it of arguments to do so," Mr Haidar said.
"It's a victory for Syria achieved thanks to our Russian friends."
China, France, the UK, the UN, the Arab League and Nato have all expressed satisfaction at the agreement.
On Saturday, US President Barack Obama said in a statement that the deal was an "important step" but urged Syria to "live up to its public commitments".
"If diplomacy fails, the United States remains prepared to act," he said. The Pentagon said the US military was still in position for military strikes.
In an interview with the ABC network on Sunday, Mr Obama confirmed that he had exchanged letters about Syria with newly-elected Iranian President Hassan Rouhani.
In an allusion to the dispute between Iran and the West over Iran's nuclear programme, Mr Obama said: "What they should draw from this lesson is that there is the potential of resolving these issues diplomatically."
"My view is that if you have both a credible threat of force, combined with a rigorous diplomatic effort… you can strike a deal," Mr Obama added.
'Last-ditch' option The timetable for the process is described by analysts as extremely ambitious.
It envisages Syria providing a full inventory of its chemical weapons in one week, all production equipment being destroyed by November, and all weapons being removed from Syria or destroyed by mid-2014.
Mr Kerry and Mr Lavrov said a UN resolution could be sought under Chapter VII of the UN charter, which allows for the use of force, if Syria fails to comply.
However the Russian foreign minister said force remained a last-ditch option.
Russia and the US have agreed on an assessment that the Syrian government possesses 1,000 tonnes of chemical agents and precursors, according to a US official.
The US believes the materials are located in 45 sites, all in government hands, half of which have useable quantities of chemical agents.
But it is thought that Russia does not agree on the number of sites, nor that they are all under the government's control.
The military leader of the anti-Assad Free Syrian Army has rejected the deal, saying it it a ploy by Russia to buy time for President Assad.
On Sunday the Syrian National Coalition, the main umbrella opposition group, demanded in a statement that the ban on chemical weapons be extended to the Syrian government's use of ballistic missiles and air power against civilian population centres.
Fighting continued inside Syria on Sunday, with heavy shelling reported by government forces on suburbs of Damascus, where fierce fighting has been taking place for several days.
Several deaths were also reported elsewhere in the country, including in the central city of Hama where the UK-based activist group the Syrian Observatory for Human Rights said that rebels, including Islamist fighters, had clashed with government forces and pro-government militias.
In comments to a press conference after talks with Israeli Prime Minister Benjamin Netanyahu, Mr Kerry said he understood the opposition's contention that removing chemical weapons would not stop the killing in Syria.
However, he insisted the deal was a "step forward" in eliminating those weapons from the government's arsenal.
Mr Netanyahu said: "What the past few days have shown is something that I have been saying for quite some time, that if diplomacy has any chance to work, it must be coupled with a credible military threat."
Mr Kerry is due to go to Paris to meet his French, British and Saudi counterparts on Monday.
More than 100,000 people have died since the uprising against President Assad began in 2011.
Millions of Syrians have fled the country, mostly to neighbouring nations. However, on Saturday, Italy's coastguard said more than 500 people, mostly Syrians, had been rescued off the Italian coast.
Millions more have been internally displaced within Syria.