WASHINGTON — The US State Department said early Saturday that there "may be" Americans still remaining in Libya after US efforts to evacuate all US nationals.

"We are aware that there may be Americans still in Libya that may need assistance departing the country," department spokesman Philip Crowley said in a statement.

"In order to help, our task force will remain up and running to make sure that if there are any Americans remaining, we can assist them," he added.

The comments came after a ferry carrying American diplomats fleeing Libya docked in the Mediterranean island of Malta on Friday, as thousands of foreigners escaped by air, land and sea amid fears of an all-out civil war.

Dozens of diplomats and their families were among the US-chartered ship's estimated 300 passengers, two of whom had to be taken off the vessel on stretchers by paramedics after crossing over from Tripoli in 20-foot (six-metre) waves.

Following the evacuation, US President Barack Obama imposed sanctions on Libya's Moamer Kadhafi and four of his sons, in a clear attempt to further weaken his teetering regime and punish brutal assaults against his people.

Crowley said that US efforts to assist Americans "will not cease now that we have suspended operations."