Galib Andang, alias Commander Robot

Andang, who was in his late 30s, was accused of leading the mass kidnapping of 21 Western tourists and Asian tourism workers on the Malaysian resort of Sipadan in April 2000.

They were held for several months on the southern Philippines island of Jolo.

Commander Robot lost a leg in the battle for his capture

Andang reportedly married one of the local hostages he snatched. The woman, a midwife, was reported to be the close relative of another Abu Sayyaf leader.

He was captured in December 2003 after a gun battle between the rebels and the military in which he lost a leg.

Alhamser Limbong, alias Commander Kosovo

Limbong was allegedly involved in the kidnapping of 20 people on the southern island of Palawan in May 2001. Most were ethnic Chinese and Filipino tourists but there were also three Americans, missionaries Martin and Gracia Burnham from Kansas, and Californian Guillermo Sobero.

The hostages were later taken into jungles on the island of Jolo. Sobero was beheaded by the Abu Sayyaf soon afterwards. Martin Burnham was killed during a rescue attempt in June 2002, but his wife survived.

Limbong was also on trial for the bombing of a ferry in Manila Bay last year, which killed more than 100 people.

Nadzmie Sabtulah, alias Commander Global

Sabtulah was the first of the Abu Sayyaf leaders to be captured, in July 2001, and had a 5m-peso ($100,000) bounty on his head.

He was accused of involvement in several kidnappings, including the Sipadan incident.

He was said to be the "intellectual" of the Abu Sayyaf group - softly-spoken, articulate, and impassioned about his Muslim cause.