JI was nurtured by Indonesian cleric Abu Bakar Bashir and his countryman Hambali, who is also known as Riduan Isamuddin and the 'Osama bin Laden of the East,' while they were in exile in Malaysia after fleeing Suharto's Indonesia.

Hambali, an Afghan war veteran, was arrested in Thailand in 2003 on suspicion of being both a top Al-Qaeda and JI operative. He is currently in detention at the US prison camp in Guantanamo Bay, Cuba.

Bashir, the alleged spiritual head of JI, was jailed in March 2005 for involvement in a conspiracy that led to the 2002 Bali nightclub bombings but was released the following year. His conviction was later overturned on appeal.

Self-proclaimed JI leaders Zarkasi and Abu Dujana, arrested on Indonesia's Java island in June 2007, were each sentenced to 15 years in prison in April 2008.

Several top JI militants are still at large, including Malaysian-born former accountant Noordin Mohammad Top, the alleged mastermind of the 2002 Bali bombings who is believed to be running a radical JI faction.

Zulkarnaen, reportedly the Al-Qaeda pointman in Southeast Asia, also remains on the run, along with bomb experts Dulmatin and Umar Patek.

Sidney Jones, a terrorism analyst with the International Crisis Group in Jakarta, said Indonesia's handling of the executions last November of three men convicted of the 2002 Bali attacks had increased the threat of reprisals. -- AFP