"We have comrades, at least six, who were killed in Madrid, everyone here has friends in Madrid," Colonel Alberto Asarta, second-in-command of the Spanish contingent, said before the mass.

But he added that "no soldier is disheartened" by Thursday's attacks claimed on behalf of the Al-Qaeda terror movement and linked to Spain's military presence in Iraq.

An improvised altar on a steel table bearing two candles and a prayer-book was erected at the foot of a mast on which a flag floated at half-mast in the dust-laden breeze.

Bareheaded, hundreds of soldiers stood in rows with their assault rifles slung on their backs, springing to attention with the arrival of their officers.

The contingent chaplain, Lieutenant Colonel Ramon Garcia Guardado, put his surplice on over his camouflage battledress before beginning the mass.

An officer, Major Fernando Ortiz Martinez, told the assembled troops: "Remembering the victims will be our way of reminding ourselves of our obligation to watch over the security of all Spaniards and all the citizens of the world."

He went on: "We soldiers are so far away, fulfilling our mission of service to the motherland in the fight against terrorism, a terrorism active all over the world which must be fought wherever it is found.

"May we accumulate sufficient moral strength to complete the defeat of terrorism."

In a sermon the chaplain also called for strength against those responsible for the attacks, whom he branded "beasts, terrorists, enemies of life."

He said that since Thursday traumatised soldiers had come to the base chapel to seek solace.

Not all the 1,300-strong contingent, most of whom belong to the 11th Infantry Brigade based in Badajoz, western Spain, were present at the service. With the shadow of Al-Qaeda threatening, security measures were strict, the base was strongly guarded and the surroundings heavily patrolled.

But some Iraqis in the predominantly Shiite area south of Baghdad have delivered messages of sympathy to the troops, who have kept in touch with their families and events in Spain via the Internet and satellite television.

A video claiming Madrid's deadly train bombings in the name of Al-Qaeda has been found and five detained men, three of them Moroccans, are being questioned, Spanish authorities said Sunday.

Ten bombs ripped apart rush-hour commuter trains, killing 200 and wounding

"We claim responsibility for what happened in Madrid exactly two and a half years after the attacks in New York and Washington," a man speaking Arabic with a Moroccan accent said on the video, according to a transcript from Spain's interior ministry.

"This is an answer to your cooperation with the Bush criminals and their allies. This is an answer to crimes which you committed in the world, notably in Iraq and Afghanistan, and there will be more, so help us God."

Interior Minister Angel Acebes said the man shown on the tape, who was dressed like an Arab, made the statement in the name of "Al-Qaeda's military spokesman in Europe... Abu Dukhan Al Afghani."

Al-Qaeda leader Osama bin Laden had threatened on October 18 to strike at Spain, Australia, Britain, Italy and other countries that helped the United States in conflicts in Afghanistan and Iraq.

Spanish Foreign Minister Ana Palacio said Sunday did not rule out collaboration between Al-Qaeda and Basque separatist group ETA, which has denied responsibility for Thursday's blasts,

WAR.WIRE