"More than 200 staff of the United Nations and foreign embassies and firms left through Sanaa airport on Saturday afternoon," one aid worker told AFP, without specifying their destination.
Another source confirmed the evacuation of UN staff, saying that only "personnel necessary for emergency humanitarian missions" remained in Yemen.
UN envoy to Yemen Jamal Benomar was also leaving Sanaa, sources close to him told AFP, adding that he would travel to the Egyptian resort of Sharm el-Sheikh to attend an Arab Summit.
Coalition forces have bombed Huthi rebel targets near Sanaa's airport, controlled by the Shiite militia.