US special forces are in Basilan

But Reuters news agency, which obtained the video from unidentified informants, said it was not possible to determine when the pictures were shot.

There has also been a reported sighting of the couple on Thursday in a remote mountain village on the southern Philippines island of Basilan.

The Philippine military, helped by US special forces, are holding military exercises in Basilan to improve their ability to fight the Abu Sayyaf rebels.

Critics of the US presence say American soldiers are actually involved in a covert operation to rescue the Burnhams, who were kidnapped from a luxury resort last May.

Al-Qaeda link

In the video, Martin Burnham listed the Abu Sayyaf's grievances:

• the "desecration" of Saudi Arabia through the presence of US and European troops;

• US support for Israel;

• Western indifference to the fate of persecuted Muslims around the world;

• sanctions against Iraq and Libya;

• support to the Philippine Government's "illegal and immoral annexation and occupation of Muslim lands" in the southern Philippines.

The statement also described the Abu Sayyaf group as the "al-Qaeda's Al Harakatul Islamiah" - the US and Philippine authorities have previously alleged the group has links to Osama Bin Laden's organisation.

Gracia Burnham sat by her husband's side throughout. Both were dressed in t-shirts, looking tired but healthy. Martin Burnham's shirt was the same one he wore in footage taken last November.

Reuters said informants who supplied the video claimed the couple had been filmed in mid-January.