All previous efforts at bringing the warring sides together for talks have failed, and it was unclear why the regime would come to the table now that it has the upper hand in the war and the threat of an imminent US military strike has been lifted.
The Russian initiative that averted the strike led to the adoption of a UN Security Council resolution to have Syria dismantle its estimated 1,000-ton chemical arsenal by mid-2014. The resolution, passed after two weeks of negotiations, marked a breakthrough in diplomatic efforts since the Syrian uprising began in March 2011.
On Monday, 20 inspectors from the Netherlands-based Organisation for the Prohibition of Chemical Weapons landed in Beirut on a private jet on their way to Syria.
The group is to travel to Damascus on Tuesday to begin its ambitious task - a complex and potentially explosive mission fraught with security challenges. They are expected to meet with Syrian Foreign Ministry officials on arrival.
Inspectors at The Hague said Sunday the inspectors' priority is to achieve the first milestone of helping the country scrap its ability to manufacture chemical weapons by a November 1 deadline, using every means possible.
That may include smashing mixing equipment with sledgehammers, blowing up delivery missiles, driving tanks over empty shells or filling them with concrete, and running machines without lubricant so they seize up and become inoperable.
Some of the inspectors will be double-checking Syria's initial disclosure of what weapons and chemical precursors it has and where they are located. Others will begin planning the logistics for visits to every location where chemicals or weapons are stored.
Within a week a second group of inspectors will arrive - fewer than 100 combined - and form teams that will fan out to individual sites. Their routes are secret - both for their safety and because Syria has the right not to reveal its military secrets, including base locations.
The inspectors have about nine months to find and dismantle an estimated 1,000-ton chemical arsenal that took years to build - the shortest deadline they have ever faced in any nation, and their first mission in a country at war.
On Monday, another UN team of inspectors charged with investigating alleged chemical attack sites concluded its almost weeklong mission in Syria and headed to Lebanon, where they boarded flights back home. The UN said Friday the team was to investigate a total of seven locations.
The team initially visited Syria last month to investigate three alleged chemical attacks earlier this year. But just days into the visit, the rebel-held Damascus suburb of Ghouta was hit by a chemical weapons attack, and the inspectors turned their attention to that case. The inquiry determined that the nerve agent sarin was used in the August 21 attack, but it did not assess who was behind it.
The team will now draft its final report on its findings about the chemical weapons attacks in Syria, expected to be ready by the end of October, according to UN spokesman Martin Nesirky in New York.
The UN resolution passed last week also endorsed a roadmap for a political transition in Syria adopted by key nations in June 2012, and called for an international conference to be convened "as soon as possible" to implement it.
But Syrian Foreign Minister Walid al-Moallem put a damper on those efforts, saying senior Damascus government officials would not sit down to talk with the Syrian National Coalition because it had supported the possibility of a US strike.
Al-Moallem told the Lebanon-based Al-Mayadeen TV late Sunday that the group "is not popular in Syria and lost a lot among Syrians when it called on the US to attack Syria militarily".
He also lashed out at the rebels when he addressed world leaders Monday at the United Nations General Assembly. He reiterated claims that his government is fighting a war mostly against al-Qaeda-linked militants.
Extremists and foreign jihadis have joined the fight in Syria, and al-Qaeda-linked rebels have proven to be some of the most effective among rebels fighting to topple the Assad regime. But they have increasingly clashed with more moderate fighters from the mainstream Free Syrian Army rebel group.
- AP
