The US is investigating whether an attack on a consulate building in Libya which left its ambassador dead was planned.
Officials suspect those behind it may have used protests over an inflammatory film as a pretext for gun and grenade attacks in Benghazi.
2 American naval destroyers have now been dispatched to waters off Libya.
A 50-strong counter-terrorism team of Marines has been deployed to strengthen security at their embassy in Tripoli.
Yesterday the US Secretary of State Hilary Clinton says she had spoken with Libyan leaders to help protect Americans working in Libya.
“I called Libyan President Magariaf to coordinateadditional support to protect Americans in Libya” she said.
“President Magariaf expressed his condemnation and condolences and pledged his government’s full cooperation”.
“In light of the events…the United States government is working with partner countries around the world to protect our personnel, our missions, and American citizens worldwide” she added.
Mrs. Clinton also condemned the attacks which happened on the anniversary of 9/11.
While US President Barack Obama has promised to bring the killers to justice.
US ambassador among the dead after Libya attack
American official killed in Libya during protests
Obama promises justice for killers of US Ambassador in Libya