The United States State Department issued a worldwide travel alert on Saturday warning of the possibility of anti-American attacks in response to the killing of two top al-Qaeda members. The warning came a day after US officials said Anwar al-Awlaki, identified as “chief of external operations” for al-Qaeda's Yemen branch, was killed in an attack by missiles fired from multiple CIA drones in Yemen. American-born Islamic leader turned al-Qaeda operative was reportedly killed on Friday by a US airstrike in northern Yemen. The former Falls Church, Virginia leader had been on the US most wanted list. The strike also killed a second U.S. citizen — Samir Khan, the co-editor of an al-Qaeda magazine — and two other unidentified al-Qaeda operatives, the Yemeni government said. Tribal leaders in the area said at least seven people were killed. They identified one of the others as al-Qaeda militant named Salem bin Arfaaj. BM