U.S. ambassador to Libya Christopher Stevens and three other embassy staff were killed in a rocket attack on Tuesday night that targeted his car in the eastern Libyan city of Benghazi, Libyan officials said on Wednesday. "The American ambassador and three staff members were killed when gunmen fired rockets at them," the officials were quoted as saying by foreign news agencies. All of the officials - three in all - hold senior security positions in Benghazi. They are deputy interior minister for eastern Libya Wanis al-Sharaf; Benghazi security chief Abdel-Basit Haroun; and Benghazi city council and security official Ahmed Bousinia.