The United States has accused Syria of organizing an angry, two-day demonstration outside the U.S. embassy in Damascus to protest Ambassador Robert Ford's visit to the besieged anti-government town of Hama. France lodged similar complaints Sunday after a pro-government mob damaged its Syria missions.

A senior State Department official said protesters called on Ford to leave the country and threw food, glass and rocks at its embassy building. The official said Ford communicated Washington's displeasure with the events – which ended late Saturday – at a previously scheduled meeting with the Syrian foreign minister requested by the U.S.

In Paris, meanwhile, France summoned Syria's ambassador to complain about damage to the French embassy in Damascus and a consulate in Aleppo – Syria's second-largest city – during similar protests .

Ford and French Ambassador Eric Chevallier traveled to Hama Thursday and Friday to show solidarity with its residents, who have come under attack from government forces while staging some of the largest protests to date against Syrian President Bashar al-Assad.

The visits have been interpreted as a strong diplomatic warning against escalating violence in the central city, which has been surrounded by tanks for a week.

Earlier, the Syrian foreign ministry said it had summoned the two envoys to protest their trips to the opposition stronghold. It called the visits “flagrant interference” in Syria's internal affairs meant to undermine the country's stability.

Mr. Assad appointed a new governor for Hama on Sunday. Anas Abdul-Razak is a medical doctor little known among opposition figures. The Syrian president last week fired his predecessor, who city residents said appeared to sympathize with protesters.

Also Sunday, Syria opened a national dialogue on political reform. Some opposition activists and intellectuals joined the talks, but most prominent Syrian dissidents boycotted the conference to protest Mr. Assad's deadly crackdown on the opposition uprising.

At the meeting, broadcast live on state television, a number of speakers condemned the government's security forces and its violence against protesters. But others repeated Mr. Assad's contention that foreign agitators are attempting to destabilize Syria.

Syrian Vice President Farouk al-Sharaa, who spoke at the event, said he hoped the two-day conference would help launch what he called Syria's transition to a “pluralistic democratic state in which all citizens enjoy equality.” Al-Sharaa acknowledged the government would not have launched such a high-level dialogue if not for the blood shed by civilians and security forces.

Mr. Assad proposed the event last month as a gesture to the opposition, which has been holding regular mass protests since March to demand an end to his family's four-decade rule of the country.

Rights groups say Syrian security forces have killed at least 1,600 civilians in the crackdown, while the government blames the violence on terrorists and Islamists who it says have killed hundreds of security personnel.