American soldiers deployed in the Philippines as part of the United States' campaign against terror have one clear message to Abu Sayyaf militants - beware, we are here.

Largely hidden away from the eyes of media since they began arriving last week, scores of U.S. troops have been quietly preparing inside a sprawling military camp in the southern city of Zamboanga for the launch of what Manila dubs a joint training exercise against local extremists linked to Osama bin Laden's Al Qaida network.

"We're very confident (of defeating terrorism)," a U.S. air force officer told Reuters in an impromptu interview inside the camp used by the Philippines' Southern Command (Southcom) as its headquarters.

"We have superior everything... the knowledge the Filipino (army) has, some of the technology we have, they (the Abu Sayyaf) should look out," he added.

Apparently in keeping with instructions for them to keep a low public profile, the officer and another U.S. soldier Reuters talked to refused to give their names. The officer kept the name written on the breast patch of his camouflage fatigues covered by a white towel.

Prior to the start of the exercises, U.S. soldiers have been keeping themselves in shape for the exercises in the jungle-clad mountains of nearby Basilan island, where the Abu Sayyaf has been holding a U.S. missionary couple hostage for eight months.

"We're staying fit, doing jogging exercises," the officer added.

Some do more than just jog. Since landing in Zamboanga, a city of about 700,000 people, a number of U.S. soldiers have also been psychologically preparing themselves for the still unseen protagonist.

"They are reading a lot of Filipino books, they are reading about the Mindanao problem, the Abu Sayyaf. They have bought a lot of books," Philippine armed forces spokesman Brigadier-General Edilberto Adan said.

The training exercises, code-named Balikatan (shoulder-to-shoulder), have further polarised this country already rent by domestic political squabblings.

While President Gloria Macapagal Arroyo's administration, business groups and an apparently substantial segment of the population back U.S. military help in quelling the Abu Sayyaf, outspoken nationalist and leftist groups have slammed the U.S. military presence as a violation of the Philippine Constitution.

A provision in the charter bars foreign troops from operating in the country unless for training. Arroyo says the Americans are not here to fight but only to train local forces in counter-terrorism methods, and that the actual fighting will be done by the locals.