WASHINGTON—The Obama administration said on Saturday it has evacuated its personnel from Tripoli as fighting between warring militias in Libya reached the capital.

Officials said the evacuation was conducted over land, with the State Department driving personnel from the American embassy in Tripoli to Tunisia. U.S. military units provided security, flying fighter jets, surveillance planes and positioning response forces in V-22 tilt rotor aircraft in the area to respond to potential threats, officials said. The evacuation...