The Philippine military says its troops have captured a camp used by the Abu Sayyaf militant group on a remote southern island. Douglas Bakshian reports from Manila.

Residents watch as government troops head to the hills for a military operation in Jolo, 29 Apr 2008

Military officials say about 300 marine and army commandoes battled 200 militants overnight, seizing the camp on Jolo island early Wednesday morning. A heavy artillery and mortar bombardment preceded the attack.

There was no immediate word on casualties or on whether any militants were captured.

Commanders describe the strike as a "surgical assault" and said it was ordered after intelligence indicated an unusual gathering of top Abu Sayyaf leaders - an indication that they were planning a major attack. Another important figure, Umar Patek, of the Indonesian-based Jemaah Islamiyah group, was also thought to be at the base.

The military says it found bomb-making supplies in the camp.

Abu Sayyaf is believed to have about 300 to 400 fighters - down from a peak of about one-thousand several years ago.

But military spokesman Major Eugene Batara says completely wiping out the group is hard because of the dense jungle on Jolo, and the militants' ability to blend in with the local community.

"It is hard for us to get to Abu Sayyaf because they are very mobile and the terrain in Jolo is really very difficult for the armed forces to go in. It is heavily forested and the terrain is in favor of the enemy because they live in that place," he explained.

Abu Sayyaf is the Philippines' most violent terrorist group. It is blamed for the bombing of a ferry near Manila Bay in 2004 that killed more than 100 people - the country's bloodiest terrorist attack.

The group says it is fighting for a homeland for the Philippines' Muslim minority population, but it is best known for kidnappings for ransom. Its members have worked with members of Jemaah Islamiyah, a group of Muslim militants blamed for deadly bombings in Indonesia.

Since 2002 the United States has been giving the Philippine military training and equipment to fight the militants. A small number of U.S. soldiers are in the southern Philippines, but are barred from combat operations.