Internationally, Morocco has maintained a moderate stance, with strong ties to the West. It was one of the first Arab and Islamic states to denounce the 9/11 terrorist attacks on the United States. In May 2003, Morocco itself was subjected to the more radical forces at work in the Arab world when Islamist suicide bombers simultaneously struck a series of sites in Casablanca, killing 45 and injuring more than 100 others. The Moroccan government responded with a crackdown against Islamist extremists, ultimately arresting several thousand, prosecuting 1,200, and sentencing about 900. Additional arrests followed in June 2004. That same month, the United States designated Morocco a major non-North Atlantic Treaty Organization ally in recognition of its efforts to thwart international terrorism. On January 1, 2006, a comprehensive bilateral free-trade agreement between the United States and Morocco took effect.