Legal challenge to US troops

Filipino troops are receiving US training

The Philippine Supreme Court has ordered the government to justify the presence of US troops in the country following a challenge by two lawyers.

The lawyers are questioning the legality of President Gloria Arroyo's decision to allow up to 650 US troops to take part in training exercises with local soldiers.

There have been regular anti-US protests

The exercises - officially launched last week - are taking place close to the southern stronghold of the rebel Abu Sayyaf, a group which the US says has links to Osama Bin Laden.

But many Filipinos are unhappy about allowing the country's former colonial power to have any military involvement.

The two lawyers said the US military presence violated a provision in the Philippine constitution which bars foreign combat troops from the country, except under a formal treaty.

"To unleash American GIs ... even under the cover of expanding the US-led war against global terror in the aftermath of 11 September, 2001, is not only an unmitigated insult against the Filipino soldier but a negation of our self-respect as a people and a mockery of the Philippine constitution," the lawyers said.

The court on Tuesday gave the presidential palace and the Department of Defence 10 days to answer the lawyers' petition.

Ransom demand

The Burnhams are being held on Basilan island

The government has continually stressed that the US troops will not take part in combat, though they are armed and can fire in self-defence.

But there has been speculation that US soldiers might launch a rescue attempt to free two American hostages being held by the Abu Sayyaf.

The Muslim group has renewed its demand for a $2m ransom for the release of Christian missionary couple Martin and Gracia Burnham, a local television network said on Tuesday.

The demand was contained in four letters written by Abu Sayyaf leader Abu Sabaya to his brother, copies of which were obtained by ABS-CBN television.

The couple, from Wichita, Kansas, are the last of dozens of hostages seized by the gunmen in a series of raids that began last May. With them is a Filipina nurse, Deborah Yap.

Both the US and Philippine Government have previously made it clear they would not pay any ransom.

The Abu Sayyaf has made kidnapping for ransom its main activity, although its stated aim is the creation of an Islamic state.