Philippine and U.S. generals were named Tuesday to oversee military exercises focused on wiping out a Muslim extremist group linked to the Al Qaeda terrorist network.

The training by 600 U.S. and 1,200 Philippine soldiers will bring U.S. troops closer to the Philippines' war against the Abu Sayyaf extremist group. As part of the exercises, U.S. soldiers will be allowed to visit the front lines as observers. 

Brig. Gen. Emmanuel Teodosio, Philippine deputy chief of staff for education and training, said Tuesday he and Brig. Gen. Donald Wurster, commander of the U.S. Special Operations Command, will co-head the exercises. 

The exercise marks increasing American involvement in the fight against the Abu Sayyaf, which has been linked to Usama bin Laden's Al Qaeda network. The United States has been supporting the poorly equipped Philippine military with weapons and training to fight the guerrillas, who have become notorious for taking foreign hostages. 

At an army camp in the southern city of Zamboanga, workers were rushing to complete training and billeting facilities for U.S. troops. 

Most of the U.S. forces are expected to arrive in Zamboanga later this month before maneuvers in February, Teodosio said. He spoke after meeting with three U.S. military officers, who did not talk to journalists. 

The Abu Sayyaf are holding missionaries Martin and Gracia Burnham from Wichita, Kan., and Filipina nurse Deborah Yap after abducting them with scores of others in a kidnapping spree that began in May. Several hostages, including Corona, Calif., resident Guillermo Sobero, were killed in captivity. Others escaped or were freed for ransoms. 

The hostages are being held on jungle-covered Basilan island, about 550 miles south of Manila. 

Defense Secretary Angelo Reyes said previous training exercises conjured "imagined" enemies. 

"Now, the current and real threat is terrorism; that's why we will be making the exercise more responsive by addressing a real threat," he told DZRH radio. "Terrorism is on Basilan, so we will do it there." 

National Security Adviser Roilo Golez said U.S. and Philippine officials were developing rules about when U.S. soldiers observing on the front lines would be allowed to fire in self-defense. 

Teodosio said most of the U.S. forces will be support personnel and maintenance crews for U.S. military aircraft. 

He said 160 troops from the U.S. special forces would be divided into 12-man teams to be merged with their Philippine counterparts. 

"Although it is very unlikely that they will be involved in actual firefight ... of course that possibility exists," Teodosio said. "But I would like to stress that the presence of the Americans here is to train, advise and assist. They will be fighting back mainly to defend themselves."