ZAMBOANGA, Philippines - Philippine troops have killed one of the top commanders of the Al Qaeda-linked Abu Sayyaf group, the military said Friday.

The death of the Islamist militant, Abdulla Ajijul, in a special operation on the southern island of Basilan Thursday is "a significant gain" in Manila's anti-terrorism campaign, regional military spokesman Major David Hontiveros said.

"He was an ASG (Abu Sayyaf Group) urban terrorist leader ... responsible for kidnapping and bombing incidents in the area," Hontiveros said.

The man had a 3.3 million peso (S$350,893) bounty on his head, Hontiveros added.

The Abu Sayyaf is a small gang of self-styled Islamist militants blamed for the country's worst terrorist attacks, including high-profile kidnappings and bombings.

Founded in the early 1990s allegedly with seed money from Osama bin Laden, the group has about 300-400 members and is on the US government's list of foreign terrorist organisations.

The military has been stepping up its attacks against the gunmen, and last week President Gloria Arroyo vowed to crush them after they beheaded a Filipino school master they had kidnapped in October.

In September, two US soldiers were killed in a roadside bomb in the deadliest attack by the Abu Sayyaf so far on American troops who have been rotating for joint training with Filipino forces since 2001.

Fighting since the start of the year have left 48 Filipino soldiers and at least 70 Abu Sayyaf militants dead, according to a tally by AFP based on official accounts.