Feb. 6, 2012 -- The United States has whisked its remaining diplomats out of Syria and suspended operations at its embassy in Damascus as violence there continues to increase, U.S. officials told ABC News.

The skeletal staff, including Ambassador Robert Ford, departed quietly despite in some cases being denied exit visas by Syrian authorities, the officials said.

"The recent surge in violence, including bombings in Damascus on Dec. 23 and Jan. 6, has raised serious concerns that our Embassy is not sufficiently protected from armed attack," State Department spokeswoman Victoria Nuland said today. "We, along with several other diplomatic missions, conveyed our security concerns to the Syrian government but the regime failed to respond adequately."

The embassy had already drawn down its staffing over the past several months amid concerns about their security. After the latest round of reductions in January a core group of only 17 remained in the country. Some departed overland to Jordan while others flew out of the airport in the capital.

The shuttering of the embassy follows similar steps by other Western countries in recent weeks. A U.S. official said that talks are ongoing with Poland to serve as the American protecting power in Syria while the U.S. embassy is closed.

Today's move comes after the Obama administration says its requests to Syrian authorities for increased security around the American embassy and its diplomats fell on deaf ears. The embassy is situated on a busy intersection in Damascus and officials say they feared al Qaeda elements, which are believed to be behind a string of car bombs in the Syrian capital, could target the Americans next. They had requested that the street the embassy is on be closed, but nothing was done.

The embassy had already been targeted by a pro-Assad mob last July after Ambassador Ford defied restrictions on his travel outside the capital and visited the restive city of Hama. Some in the crowd scaled the outer walls of the embassy and defaced the exterior, including the American flag, before being chased away by embassy guards.

The U.S. embassy, like other diplomatic facilities there, is guarded by Syrian security forces. U.S. officials say they were slow to respond and accused the government of sponsoring the protest.

Similar mobs have targeted Ambassador Ford's convoy when he went to visit a prominent opposition leader in September. Ford and his staff barricade themselves in the leader's office for several hours before Syrian security finally arrived to disperse the crowd. As they left the pro-Assad protestors pelted the cars with rocks, eggs, and tomatoes, damaging one of them significantly, officials said at the time.

The Syrian government's crackdown on the movement to oust President Assad has become increasingly bloody in recent months. The United Nations stopped counting the dead late last month, saying it was too hard to keep up with and verify the body counts. At the time it placed the death toll at more than 5,400. Since then there have been reports of hundreds more killed.

Opposition elements have also stepped up efforts to fight back, raising fears that the once peaceful movement could evolve into a civil war.

Ambassador Ford has been one of the most vocal critics of the Assad government over the past year. In August President Obama called on Assad to step down, and the United States has supported resolutions in the United Nations Security Council that would do the same.

The latest effort at the United Nations, proposed by Morocco and backed by the Arab League, was vetoed on Saturday by Russia and China who have maintained support for President Assad and are reluctant to endorse another resolution that could lead to foreign intervention like in the case of Libya.