By OLIVER TEVES
.c The Associated Press

ZAMBOANGA, Philippines (June 21) - A Muslim guerrilla leader whose fighters kidnapped two Kansas missionaries and scores of other people was shot in a clash with U.S.-trained troops Friday and may be dead, President Gloria Macapagal Arroyo said Friday.

Navy personnel were searching the waters off southern Mindanao island for the body of Abu Sabaya, the most visible of the extremist group's commanders, who often called local media with demands and statements taunting the government.

He was one of three guerrillas who jumped off a boat after being wounded in a firefight with elite navy troops, Arroyo said. She said four guerrillas were captured. A soldier told his superiors that he shot Sabaya in the back and saw his body sink in the water, officials said.

''The captured Abu Sayyaf members confirmed that one of those who jumped into the sea was Abu Sabaya, who was wearing a black sweat shirt,'' the president said. ''The (military) team also confirmed shooting the man in the black sweat shirt.''

The Philippine military said it had been hot on Sabaya's trail since two of the group's last three hostages - American Martin Burnham and Filipina Ediborah Yap - were killed during a June 7 clash along with three rebels. Burnham's wife, Gracia, was rescued injured but alive. Washington recently offered a $5 million bounty for Abu Sabaya's capture.

''We did get word from the (Philippine military) that Abu Sabaya was one of those killed in the encounter,'' said Maj. Richard Sater, a spokesman for U.S. forces conducting a counterterrorism training exercise aimed at helping local troops wipe out the Abu Sayyaf, who are believed to have links to Osama bin Laden's al-Qaida network. ''We are encouraged. It is a step forward in the war against terrorism.''

Arroyo, who repeatedly has vowed to crush the Abu Sayyaf, congratulated the military in a written statement, adding:
''Terrorists will be hunted down relentlessly wherever they are. They will be given no room to maneuver, to hide, or to rest. We will not stop until they are all accounted for.''

She said the clash occurred around 4:30 a.m. half a mile offshore in Zamboanga del Norte province, site of the June 7 clash.

Sater said Americans provided unspecified support during the clash but were not directly involved in the fighting.

''We're here to advise and assist. We helped out in that capacity this morning, providing some surveillance and communication, that sort of thing,'' Sater said. Asked whether Americans were nearby, Sater said: ''Yes, but I can't say how near.''