US secretary of state Hillary Clinton today condemned an attack on the US ambassador in Damascus and demanded that Syria take steps to protect US diplomats.
"We condemn this unwarranted attack in the strongest possible terms. Ambassador (Robert) Ford and his aides were conducting normal embassy business and this attempt to intimidate our diplomats through violence is wholly unjustified," Ms Clinton said.
"We immediately raised this incident with the Syrian government and we are demanding that they take every possible step to protect our diplomats according to their obligations under international law."
Earlier supporters of Syrian president Bashar al-Assad threw stones and tomatoes at Mr Ford and other US diplomats who were visiting an opposition figure in Damascus on today, sources said.
"Two embassy cars were damaged. The US delegation is still there and the crowd is surrounding the building," said the witness.
"They are chanting 'Abu Hafez [father of Hafez]'," the witness said, a nickname for Dr Assad.
The witness said the diplomats were visiting Hassan Abdelazim, a centrist politician who has been demanding an end to a crackdown on a six month pro-democracy uprising as a condition for any talks with Dr Assad.
It was the second attack on US diplomats since the pro-democracy uprising erupted in Syria in March. In July, following a visit by Mr Ford to the city of Hama, scene of large demonstrations for political freedoms, Assad supporters attacked the US embassy compound in Damascus.
Mr Ford has infuriated Syria's rulers by cultivating links with the grassroots protest movement. He was cheered by protesters when he went in July to the city of Hama, which was later stormed by tanks. He also visited a town that has witnessed regular protests in the southern province of Deraa, ignoring a new ban on Western diplomats travelling outside Damascus and its outskirts.
The United States, seeking to convince Dr Assad to scale back an alliance with Iran and backing for militant groups, moved to improve relations with Dr Assad when President Barack Obama took office, sending Mr Ford to Damascus in January to fill a diplomatic vacuum since Washington pulled out its ambassador in 2005.
But ties deteriorated after the uprising broke out, and Dr Assad ignored international calls to respond to protester demands that he dismantle the police state and end five decades of autocratic rule.
Reuters