Government forces recovered several homemade bombs left behind by fleeing Abu Sayyaf gunmen in the hinterlands of Lantawan town in Basilan island, about 15 miles north of Zamboanga, a port city in southern Philippines, officials said.

The bombs were assembled with chemicals commonly used as fertiliser and had electronic timers, said Basilan Army chief Hermogenes Esperon.

The bombs were also made from sodium nitrate, which is widely available in Zamboanga City and used by fishermen in illegal fishing, other officials said.

The extensive arsenal of the group is clear proof that it was behind the recent bombing in three hotels in Zamboanga, said Esperon. The recovery of the explosives came four days after the bombing of two hotels in Zamboanga City.

The October 8 bombing of Paradise and Imperial hotels in Zamboanga City was the handiwork of the militant group, said Southern Command chief Lt-Gen Roy Cimatu.

"It was part of the group's diversionary tactics at a time when they were relentlessly pursued by the military," Cimatu said.

At least eight Abu Sayyaf members were behind the blasts in Zamboanga City, but four of the bombers were later killed in the village of Balatanay here after troops clashed with a militants.

"The militants were also targeting Isabela City and four bombs were supposed to have exploded in different targets in Isabela, Cimatu said.

The group is still holding two American and 12 Filipino hostages in Basilan.

Adds Noralyn Mustafa Our Jolo Correspondent:Suspected terrorists have entered Basilan, near Zamboanga, a port city in southern Philippines, said Hermogenes Esperon, a brigade commander. They have met Abu Sayyaf leaders, Khadaffy Janjalani and Abu Sabaya, said Esperon.

He added that the meeting could be connected with the Abu Sayyaf's plan to counter the entry of more than two dozen U.S. experts who were scheduled to be in Basilan for 10 days, starting next week.

Many believe that the Abu Sayyaf Group has links with Saudi-born millionaire Osama bin Laden and his terrorist network, Al Qaida.