A team of UN chemical weapons experts, in Syria to investigate alleged use of the banned arms, left their Damascus hotel on Thursday afternoon, an AFP correspondent said.
It was unclear where the team, which left in a three-car convoy, was headed.
The experts arrived in Syria on Wednesday on their second mission to the country, where they will examine some 14 alleged incidents involving the use of chemical weapons.
On their earlier mission, the team investigated an August 21 attack in the outskirts of Damascus that reportedly killed hundreds of people.
Its report, submitted to the United Nations, confirmed that sarin was used, but did not apportion blame for the attack.
Washington and other backers of the Syrian rebels have accused the Syrian regime of carrying out the attacks, a claim that the government denies.