(CNN) -- 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," U.S. President Barack Obama said in a statement 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.
It was unclear what steps the United States was taking elsewhere in the world.
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, Secretary of State Hillary Clinton said Wednesday.
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 the administration of President Bill Clinton.
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.
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.
"The question will be, once the dominoes fell in Cairo and protests started to occur, what was requested and what was done," he said.
No U.S. Marines were guarding the consulate at the time of the attack, according to U.S. officials. But that is not necessarily unusual, Burton said.
"Having the Marines can be viewed as politically sensitive at times," Burton said.
It can also raise the profile of an installation and invite unwanted attention or attacks, he said.
Diplomats in unstable regions typically travel in convoys of heavily armed guards, and it's likely that Stevens was well-guarded, said Christopher Hill, former U.S. ambassador to Iraq.
"I can assure you, I can absolutely assure you, that security was paramount on the minds of the embassy and the ambassador," Hill said.
But he said it's just not possible to surround diplomats in a bubble of impenetrable protection.
"It's never a matter of getting rid of risk. It's a matter of managing risk, and that is a very tough thing to do," he said.
Stevens' death, however, will spark a thorough review of security practices and could result in changes to how diplomats are protected, Burton said. Something similar happened after the 1983 bombing of the U.S. Embassy in Beirut, Lebanon, sparked new construction and security standards for embassies, Burton said.
"My gut tells me that this will cause that to happen," he said.
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By Michael Pearson - CNN
CNN's Barbara Starr contributed to this report.
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