The Obama administration is preparing to close its embassy in Syria as the security situation there continues to deteriorate, a State Department official tells ABC News.

The official said that if the Syrian government does not provide more security for the embassy, the U.S. is preparing to pull out its remaining personnel, including Ambassador Robert Ford, and to "shutter" the embassy within weeks.

The government of President Bashar al-Assad has not responded to repeated requests for additional security for the embassy, which has already been the subject of attacks in the past year by pro-government mobs.

The decision was first reported by the Washington Post, which reported that the decision to shutter the embassy comes after a series of car bombs in Syria that are blamed on elements of al Qaeda.

The news was confirmed later today by the State Department: "While no decision has been made, we have serious concerns about the deteriorating security situation in Damascus, including the recent spate of car bombs, and about the safety and security of embassy personnel. We have requested that the government of Syria take additional security measures to protect our embassy, and the Syrian government is considering that request. We have also advised the Syrian government that unless concrete steps are taken in the coming days we may have no choice but to close the mission."

The United States has been shaving its roster in Syria for the past several months as the security situation deteriorates. It pulled out more staff just last week, and officials say they are now down to the "bare bones."

Ambassador Ford himself was pulled out last fall over concerns about his safety. He returned to the country in December. Ford has been targeted by pro-government groups that have thrown rocks at his convoy and once trapped him inside the office of an opposition leader. Government was slow to respond, officials said at the time.

Ambassador Ford has been one of the Assad government's most vocal critics inside Syria. He has defied government bans on travel by diplomats and has visited several restive cities. Those visits have resulted in increased harassment of the U.S. diplomatic mission in Syria.

The United States has joined its allies in calling on Assad to step down.