Because of that, US soldiers participating in an annual joint exercise with Philippine troops here and in Nueva Ecija are barred from venturing beyond the exercise areas to avoid possible terrorist attacks, Capt. Burrel Parmer told reporters.
But Parmer downplayed the advisory, explaining that no threat seemed imminent and that the advisory has been in effect since previous joint exercises. He said the threat of terrorism is worldwide.
US troops were warned against venturing outside the exercise areas for fear of possible terrorist attacks in the past.
US officials are satisfied with the security provided by Philippine forces, Parmer added.
Yesterday, the roar and drone of aircraft engines filled the skies over nearby Angeles City and Mabalacat town as US jets and helicopters flew training maneuvers at the start of the two-week exercises, dubbed "Talon Vision."
"We’re here to train and learn from each other and that’s our focus, and there is no planned leave or liberty in the Philippines while we’re here," Col. Steven Busby, the US co-director of the exercise, told reporters. "Our men are expected to dedicate their time in the trainings."
Some 830 US marines and sailors, mostly based in Okinawa, Japan, are participating in the maneuvers with 800 Philippine Army and Air Force troops.
Opening ceremonies were held here, a former US air force base 80 kilometers north of Manila.
The annual drills train troops in airborne operations, skydiving, sky rappelling and other maneuvers and aim to improve interoperability by sharing tactics and procedures, officials said.
Busby said 20 US aircraft will be used — four different types of helicopters and two KC-130 Hercules planes.
Aside from Clark, exercises are being held at Fort Magsaysay, an Army base in Laur, Nueva Ecija, and at a military installation in Ternate, Cavite, Parmer said.
Busby said the US forces also will be taking part in civic projects like building schools and providing medical and dental services for the local community.
A separate US military group has been providing training in Zamboanga City to Filipino counterparts involved in assaults against Muslim extremist guerrillas.
US and Philippine officials are still negotiating the terms of a larger counter-terrorism exercise called "Balikatan" (Shoulder-to-Shoulder), to be held in Sulu.
A similar exercise last year bolstered a Philippine military offensive that crippled the Abu Sayyaf in Basilan.
The Philippines and the United States have worked together in fighting both local and foreign Muslim extremists allegedly linked to such groups as Jemaah Islamiyah and the al-Qaeda terrorist network.
During his brief visit to Manila in October, US President George W. Bush praised the Philippines’ efforts to combat terrorism and pledge to help its long-time ally.
Washington considers the Abu Sayyaf, the Communist Party of the Philippines and its armed wing, the New People’s Army, as terrorist organizations.
The Abu Sayyaf Islamic kidnap gang is notorious for abducting foreigners for ransom and while the Communist Party of the Philippines has been fighting an insurgency for over 30 years. — With Ric Sapnu, AP