The United States moved to increase embassy security around the world after the attack that killed the U.S. ambassador to Libya and three staffers.

"I have directed my administration to provide all necessary resources to support the security of our personnel in Libya, and to increase security at our diplomatic posts around the globe," President Barack Obama said in a statement issued Wednesday morning in response to the attack.

The United States deployed a group of Marines called a Fleet Antiterrorism Security Team to Libya to help secure U.S. facilities, two U.S. officials said Wednesday. Such units are specially trained to retake or guard diplomatic installations and other U.S. facilities in troubled regions.

About 50 Marines were headed to Tripoli and could deploy elsewhere in Libya after their arrival, U.S. officials said.

Other U.S. troops and units abroad have been notified they could be ordered to move to embassy installations around the world to provide additional security, a senior U.S. military official said.

The official added that the Pentagon is involved in intensive discussions with the State Department and White House on how to implement Obama's order to step up diplomatic security.

"We are looking at the requirements, what we need and identifying what assets could have to move," the official said, adding that could include troops, aircraft, ships and other equipment if needed.

Two U.S. Navy warships were moving toward the Libyan coast Wednesday, two U.S. officials said. Both are equipped with Tomahawk missiles that could be used if a strike was ordered, which "will give the administration flexibility" if action is ordered against targets in the country, a senior official said.

The moves come a day after the attack that killed Ambassador J. Christopher Stevens amid protests at the U.S. Consulate in Benghazi, Libya. Heavily armed protesters assaulted the consulate, said Secretary of State Hillary Clinton.

Demonstrators also attacked the U.S. Embassy in Cairo on Tuesday. Protesters in both countries were apparently angry about an online film considered offensive to Islam.

On Wednesday, the State Department urged Americans to avoid the area around the embassy in Kharthoum, Sudan, due to "anti-U.S. protests outside." There was no immediate word of violence.

"There's a lot of skittish people at the State Department right now," CNN foreign affairs reporter Elise Labott said.

It is unclear whether Stevens' death resulted from the broader anti-American protests or a separate, local plot against the ambassador, former State Department official James Rubin said.

"Until you are able to answer that question, it's kind of hard to assign the significance of this," said Rubin, who was State Department spokesman during President Bill Clinton's administration.

Mohammed Al-Megaryef, head of Libya's ruling party, told reporters Wednesday that "the transitional government has done all that it could in order to protect the embassies, the consulates and the foreign companies in Libya."

Secretary of State Clinton said she had spoken to the Libyan president seeking additional protection for American interests in the country.

She said the U.S. government is also working with countries to "protect our personnel, our missions and American citizens worldwide."

"There is no higher priority than protecting our men and women, wherever they serve," Clinton said.

Libyan Prime Minister Abdurrahim el-Keib said the government would increase security Wednesday in response to the attacks.

Security outside embassies is the responsibility of the host country, and it's "entirely possible" that U.S. officials asked for but didn't receive help to push back the attackers that ultimately killed Stevens and the other staffers, said Fred Burton, a Stratfor analyst and former State Department counterterrorism agent.