Indonesia's president warned Friday that terrorism was still a threat to the world's most populous Muslim country, which has not suffered a major attack in nearly three years following a crackdown on Islamic militants. President Susilo Bambang Yudhoyono said in a State of the Union address before Parliament that "our country is still unsafe from terrorist acts," although efforts to overcome extremism "have shown an encouraging progress." "Various achievements are very heartening to all of us, but we must continue to heighten our vigilance," he said, praising authorities for arresting and prosecuting hundreds of suspected Islamic militants. The arrests highlighted the lingering threat in Indonesia, which has been thrust onto the front lines in the war on terrorism in recent years by a string of attacks. Regional militant group Jemaah Islamiyah has been blamed for a series of bombings in Indonesia, including those on Bali island in 2002 and 2005, as well as Jakarta's J.W. Marriott Hotel and the Australian Embassy in the 2003 and 2004.