US troops in the southern Philippines could move closer to combat zones as the two countries consider extending their joint military exercises.

US Deputy Defence Secretary Paul Wolfowitz, who is visiting the Philippines, said on Monday that Washington was open to the idea of keeping troops there after its mandate expires next month.

Wolfowitz : No combat role for US

Since early this year about 1,000 US troops have been training Philippine soldiers to combat Abu Sayyaf rebels, which the US links to the al-Qaeda global militant network.

Foreign troops are banned under the Philippines' constitution from taking part in any fighting, but the US troops are fully armed and can fire in self-defence.

"Our president has said over and over again that this war against terrorism is going to be a long struggle," Mr Wolfowitz said in Manila, before flying to the southern island of Basilan.

Controversial idea

Mrs Arroyo has said she favours deploying US troops closer to the front lines to enable them to better train local soldiers.

"If they go down to company level in their training, I think the [training exercises] would be all the more effective," she said in a radio programme.

We are not talking about sending US troops to do the jobs for the Philippine Armed Forces

Paul Wolfowitz, US Deputy Defence Secretary

US media reports have said the Defence Department is considering a recommendation for military advisers to join patrols on Basilan so they may give on-the-spot advice in the pursuit of the rebels.

But Mr Wolfowitz has made it clear that anything which puts US troops in any kind of combat role is out of the question.

"We are not talking about sending US troops to do the jobs for the Philippine Armed Forces," he said. "What we are about here is improving the capabilities of the Philippine Armed Forces to do the job themselves."

Old memories

The presence of US troops is highly controversial because the US used to be the colonial power in the Philippines.

Philippine Defence Secretary Angelo Reyes said there was no decision yet about whether to extend the joint exercises.

"If the situation calls for it, then we will have it," he said.

The Abu Sayyaf rebels have held hostage an American missionary couple and a Filipina nurse for more than a year.

They are being held somewhere in the jungles of Basilan, not far from military camps where most of the joint exercises have been taking place.