Syrian government supporters attacked the US Embassy in Damascus today in protest over the ambassador's recent visit to an opposition stronghold.
They smashed windows, raised a Syrian flag and scrawled graffiti calling the American ambassador a "dog".
French Embassy security guards in the capital fired in the air to hold back supporters of President Bashar Assad's regime who were also protesting at the French ambassador's visit to the same city, Hama, in central Syria.
Protesters smashed embassy windows and shattered the windshield of a diplomatic SUV outside the compound. The French flag was removed and replaced with a Syrian one.
"God, Syria and Bashar. The nation that gave birth to Bashar Assad will not kneel," read graffiti written outside the embassy. One witness said three protesters were injured when guards beat them with clubs. The witness asked not to be identified because of the sensitivity of the situation.
A US official said the Obama administration will formally protest over the attack and may seek compensation for damage caused when a mob breached the wall of the compound before being dispersed by Marine guards.
The Syrian regime called the French and American ambassadors' visits to Hama last week interference in the country's internal affairs and accused the envoys of undermining Syria's stability.
The protests erupted after US Ambassador Robert Ford harshly criticised the Syrian government's crackdown on a popular uprising.
Some 1,600 civilians and 350 members of security forces have been killed since demonstrations began, activists say. Syria blames what it calls "armed gangs" and Muslim extremists for the violence.
Hiam al-Hassan, a witness, said about 300 people had gathered outside the French Embassy while hundreds others were at the American diplomatic compound.
"Syrians demonstrated peacefully in front of the French embassy but they were faced with bullets," said al-Hassan.
On Sunday, Mr Ford attacked the Syrian government for allowing pro-government protests while beating up anti-regime demonstrators. The pro-Assad protests in Syria are known as "mnhebak," or "we love you."
"I have not seen the police assault a "mnhebak" demonstration yet," Mr Ford wrote on the embassy's Facebook page. "On July 9, a "mnhebak" group threw rocks at our embassy, causing some damage. They resorted to violence, unlike the people in Hama, who have stayed peaceful."
"And how ironic that the Syrian Government lets an anti-US demonstration proceed freely while their security thugs beat down olive branch-carrying peaceful protesters elsewhere," he said. "I saw no signs of armed gangs anywhere not at any of the civilian street barricades we passed," Ford added.
The protests coincided with government-organised talks in Damascus on possible political reforms after four months of unrest.
However the talks did not stop Syrian forces from pressing their crackdown on the opposition.
Before the embassy attacks, Syrian troops stormed the country's third-largest city with armoured personnel carriers and heavy machine guns, a rights activist. At least two people were killed and 20 wounded in the attacks in Homs, activists said.
The clashes in Homs in central Syria suggest the Assad regime will not ease its four-month-old crackdown on the opposition despite proposing some political changes.