Libya was strongly affected by the Arab Spring. Anti-government protests broke out in Benghazi, Libya, in February 2011, and the Gaddafi government responded with military force. The Obama administration initially resisted calls to take strong action but relented after the Arab League requested Western intervention in Libya. In March 2011, international reaction to Gaddafi's military crackdown culminated in a United Nations resolution to enforce a no fly zone in Libya. Obama authorized U.S. forces to participate in international air attacks on Libyan air defenses using Tomahawk cruise missiles to establish the protective zone. The intervention was led by NATO, but Sweden and three Arab nations also participated in the mission. With coalition support, the rebels took Tripoli the following August. The Libyan campaign culminated in the toppling of the Gaddafi regime, but Libya experienced turmoil in the aftermath of the civil war. Obama's intervention in Libya provoked criticism from members of Congress and ignited a debate over the applicability of the War Powers Resolution. In September 2012, Islamic militants attacked the American consulate in Benghazi, killing Ambassador J. Christopher Stevens and three other Americans. Republicans strongly criticized the Obama administration's handling of the Benghazi attack, and established a select committee in the House to investigate the attack. After his presidency, Obama acknowledged his "worst mistake" of his presidency was being unable to anticipate the aftermath of ousting Gaddafi.