Washington, Sep 16 (IANS): The US State Department has ordered "non-essential staff" to leave Sudan and Tunisia where anti-American protests have broken out over a film that allegedly insults Islam, a top official said.

"Given the security situation in Tunis and Khartoum, the State Department has ordered the departure of all family members and non-emergency personnel from both posts, and issued parallel travel warnings to American citizens," Xinhua quoted State Department spokeswoman Victoria Nuland as saying.

US embassies in Sudan and Tunisia came under attack from protesters, as a fresh wave of violence sparked by the controversial film targeted American diplomatic missions in a number of countries.

In Tunis, at least three protesters died in clashes. In Khartoum also, three people were killed as protesters attempted to force their way into the US embassy.

The protests prompted the State Department to warn Americans against travelling to the two countries.

"The airport in Tunis is open and US citizens are encouraged to depart by commercial air," the department said in a travel alert.

"The Department of State warns US citizens of the risks of travelling to Sudan, urges US citizens to avoid all travel to the Darfur region of Sudan, the Blue Nile and Southern Kordofan states, and advises you to consider carefully the risks of travel in other areas of Sudan," the travel warning said.

"The terrorist threat level throughout Sudan, and particularly in the Darfur region, remains critical," it added.

US Ambassador to Libya Christopher Stevens and three other embassy officials were killed, when hundreds of protesters broke into and set ablaze the US consulate building in Benghazi, Libya's second largest city.