"All remaining US citizens who wish to depart Egypt on a US government flight and who are able to do so should immediately proceed to the HAJ Terminal 1, Hall 4 as soon as possible on February 3," the State Department said in a statement, referring to the location within Cairo's international airport.

"Additional US government flights after Thursday are unlikely."

Days of protests turned increasingly violent in the key US ally, with gunfire aimed at anti-regime protesters leaving at least two dead in Cairo's central Tahrir, or Liberation, Square in the early hours Thursday.