ISLAMIC DEFENDERS FRONT Formed: 1998 Leader: Habib Rizieq Shihab Membership: Claims to have 15 million members, seven million of which are militants trained in martial arts Headquarters: Active in Jakarta, parts of Sumatra, as well as central and east Java The largest militant group in the country threatened to 'expel' Americans from Indonesia prior to the U.S. attack on Afghanistan. Also known for launching violent raids on nightclubs and bars in the capital over the past few years. Leader questioned for nearly 12 hours last week over recent raids staged by the group in Jakarta