The United States joined NATO in military intervention in Libya, which led to the death of Muammar Gaddafi. In May 2011 Navy SEALS killed Al-Qaeda leader Osama bin Laden. On September 11, 2012, members of Ansar al-Sharia attacked the American diplomatic compound in Benghazi, resulting in the deaths of U.S. Ambassador to Libya J. Christopher Stevens and three other Americans. The United States stepped up drone attacks in Pakistan, Somalia, and Yemen, targeting Yemeni-American Muslim cleric Anwar al-Awlaki on September 30, 2011. His 16-year-old son, American-born Abdulrahman al-Awlaki, was killed two weeks later.