U.N. Secretary-General Ban Ki-moon is in Tripoli on a previously unannounced visit to Libya, his first since the uprising that toppled its long-time dictator Moammar Gadhafi.

Mr. Ban arrived in Tripoli Wednesday. His office said he would meet with members of Libya's ruling National Transitional Council and civil society representatives for several hours before departing.

Libya's NTC appointed Abdurrahim el-Keib as its new interim prime minister late Monday. The American-educated engineering professor said he will make respect for human rights a priority as he forms an interim government and prepares the country for its first free elections next year.

Human rights groups have expressed concern about the NTC's treatment of pro-Gadhafi fighters and African migrants during the eight-month uprising that ended with the former leader's killing last month.

The U.N. secretary-general is expected to arrive in the French city of Cannes later in the day to attend a summit of the Group of 20 economic powers.