Unidentified snipers have opened fire on a convoy of UN experts investigating suspected chemical weapons attacks in Syria's capital, the UN has said.
One car was shot at "multiple times", forcing the convoy to turn back.
Syrian state media blamed opposition "terrorists" for the attack, though the claim could not be verified.
The UN team later resumed its mission, entering the western district of Muadhamiya to gather evidence, before reportedly returning to Damascus.
Hundreds died in alleged attacks on Wednesday in five districts near Damascus.
The US said there was little doubt Syrian forces used chemical weapons in the attacks, which reportedly killed more than 300 people in rebel-held areas.
Syrian President Bashar al-Assad dismissed the accusation as "an insult to common sense" and warned the US against military intervention.
"If someone is dreaming of making Syria a puppet of the West, then this will not happen," he told the Russian newspaper Izvestiya.
The 20-member UN inspection team has been in Syria since 18 August to look into three earlier suspected chemical attacks.
The UN inspectors have been talking to doctors in Muadhamiya
The experts intend to take soil, blood, urine and tissue samples for laboratory testing from the five locations on Monday and Tuesday but they are unlikely to apportion blame for any of the attacks.
Video footage posted online showed UN inspectors in Muadhamiya taking samples and talking to residents.
They went to a Red Crescent centre and spoke to doctors, opposition activists said.
Shortly after setting out from their hotel in Damascus, their cars came under fire "multiple times by unidentified snipers", according to a statement from the UN.
The team returned safely back to the government checkpoint before setting out again.
The convoy was "deliberately targeted" and it seemed someone was trying to intimidate the team, the UN Secretary General's spokesman, Farhan Haq, told the BBC.
Full story and updates available at BBC.