By Andrew Quinn and Khaled Yacoub Oweis
WASHINGTON/AMMAN (Reuters) - Syria's President Bashar al-Assad has lost legitimacy and is "not indispensable," U.S. Secretary of State Hillary Clinton said on Monday as tensions soared over an assault by Assad loyalists on the U.S. and French embassies in Damascus.
Clinton condemned the Syrian attacks and said Washington did not believe the long-time Syrian ruler would follow through on his promises to reform in the face of escalating protests against his rule.
"From our perspective, he has lost legitimacy, he has failed to deliver on the promises he's made, he has sought and accepted aid from the Iranians as to how to repress his own people," Clinton told reporters in an appearance with European Union foreign policy chief Catherine Ashton in Washington.
Clinton's comments marked a significant sharpening of U.S. rhetoric on Assad, whose security forces have waged an increasingly brutal crackdown against protesters inspired by pro-democracy movements elsewhere in the Arab world.
Several Assad loyalists broke into the U.S. embassy in Damascus on Monday and security guards used live ammunition to prevent hundreds from storming the French embassy, diplomats said.
They said the attackers tore down U.S. embassy plaques and tried to break security glass in protests fueled by the government against a visit by U.S. and French ambassadors to the city of Hama, focus of protests against Assad's rule.
"Four buses full of shabbiha (Alawite militia loyal to Assad) came from Tartous. They used a battering ram to try to break into the main door," a resident of Afif, the old district where the U.S. embassy is located told Reuters by telephone.
A Western diplomat in the Syrian capital said: "This is a violent escalation by the regime. You do not bring busloads of thugs into central Damascus from the coast without its consent."
A French foreign ministry official said the Syrian authorities had done nothing to stop the assault.
"(France) reminds (Syria) that it is not with such illegal methods that the authorities in Damascus will turn the attention away from the fundamental problem, which is to stop the repression of the Syrian population and to launch democratic reform," foreign ministry spokesman Bernard Valero said.
France has led Western attempts to pass a United Nations Security Council resolution condemning Syria's hierarchy for cracking down on protesters. It says the president has lost legitimacy because of the number of killings to try to quell the protests demanding political freedoms after 41 years of Assad family rule.
The United States, which sees Syria as a fragile but crucial element of any lasting Middle East peace equation, had been reluctant to take that step, but Clinton's comments on Monday indicated Washington's patience had run out.
"If anyone, including President Assad, thinks that the United States is secretly hoping that the regime will emerge from this turmoil to continue its brutality and repression, they are wrong," Clinton said.
"President Assad is not indispensable and we have absolutely nothing invested in him remaining in power."
The United States condemned Syria for "refusing" to protect the embassy from an assault it said had been encouraged by a pro-government television station, and called in a senior Syrian diplomat to deliver a formal complaint.
Human rights groups say at least 1,400 civilians have been killed since an uprising began in March against Assad's autocratic rule, posing the biggest threat to his leadership since he succeeded his father 11 years ago.
Assad loyalists also attempted to attack the U.S. ambassador's residence in Damascus on Monday after assaulting the embassy compound but failed to gain entry.
"It was the same thing, a mob. But everybody is alright," a U.S. official said, adding that U.S. Ambassador Robert Ford was at the embassy compound when the assaults occurred and not the residence, located several blocks away.
In other violence on Monday, Syrian forces killed a civilian and wounded 20 in heavy-machinegun fire on Homs, Syria's third city, and went house-to-house arresting suspected opponents in Hama, human rights activists said.
Mostafa Abdelrahman, a preacher at a mosque in Hama, met Assad on Sunday to demand the release of 1,000 political prisoners and offer to remove makeshift roadblocks if given guarantees there would be no more assaults, activists said.
Despite using military assaults in towns and cities to try to crush the protests, Assad has called for talks on reforms. But the opposition refused to attend a two-day conference this week in the capital, saying it was futile as long as violence continued. Mostly Assad supporters were taking part.
"Dialogue can only work when both parties respect each other and look at each other as equals," said Ayman Abdel-nour, the Gulf-based editor of all4syria.com website.
Vice President Farouq al-Shara, whose role is ceremonial, told the conference's opening ceremony on Sunday the authorities would turn over a new page, hinting that political parties other than the ruling Baath party would be allowed to operate.
The meeting was expected to discuss legislation which would allow a multi-party system and constitutional amendments.
(Additional reporting by Oliver Holmes in Beirut and by Paris and Washington bureaux; Editing by Elizabeth Piper and Paul Simao)