Philippine police have found a headless body of a Muslim farmer believed to have been executed by guerrillas linked to Osama bin Laden's Al Qaida network, officials said yesterday.

The body was found in the municipality of Maluso on Basilan island, where the Abu Sayyaf guerrillas have been holding a U.S. missionary couple and a Filipina nurse hostage for over eight months.

The United States has listed the Abu Sayyaf as among groups supporting bin Laden and Al Qaida, prime suspects in the September 11 attacks on U.S. landmarks in New York and Washington.

"We believe this was the handiwork of the Abu Sayyaf," Philippine army brigade commander Colonel Alexander Aleo told reporters. "We are still searching for the head."

Investigators have not established the motive behind the man's execution.

The Abu Sayyaf claims to fight for an Islamic state in the south of the mainly Catholic Philippines but pursues kidnap for ransom as its main activity.

It has beheaded some of its kidnap victims, including Californian tourist Guillermo Sobero, who was executed in June last year.