Commanders in Afghanistan are bracing themselves for possible riots and public fury triggered by the publication of "trophy" photographs of US soldiers posing with the dead bodies of defenceless Afghan civilians they killed.

Senior officials at Nato's International Security Assistance Force in Kabul have compared the pictures published by the German news weekly Der Spiegel to the images of US soldiers abusing prisoners in Abu Ghraib in Iraq which sparked waves of anti-US protests around the world.

They fear that the pictures could be even more damaging as they show the aftermath of the deliberate murders of Afghan civilians by a rogue US Stryker tank unit that operated in the southern province of Kandahar last year.

Some of the activities of the self-styled "kill team" are already public, with 12 men currently on trial in Seattle for their role in the killing of three civilians.

Five of the soldiers are on trial for pre-meditated murder, after they staged killings to make it look like they were defending themselves from Taliban attacks.

Other charges include the mutilation of corpses, the possession of images of human casualties and drug abuse.

All of the soldiers have denied the charges. They face the death penalty or life in prison if convicted.

The case has already created shock around the world, particularly with the revelations that the men cut "trophies" from the bodies of the people they killed.

An investigation by Der Spiegel has unearthed approximately 4,000 photos and videos taken by the men.

The magazine, which is planning to publish only three images, said that in addition to the crimes the men were on trial for there are "also entire collections of pictures of other victims that some of the defendants were keeping".

The US military has strived to keep the pictures out of the public domain fearing it could inflame feelings at a time when anti-Americanism in Afghanistan is already running high.

In a statement, the army said it apologised for the distress caused by photographs "depicting actions repugnant to us as human beings and contrary to the standards and values of the United States".

The lengthy Spiegel article that accompanies the photographs contains new details about the sadistic behaviour of the men.

In one incident in May last year, the article says, during a patrol, the team apprehended a mullah who was standing by the road and took him into a ditch where they made him kneel down.

The group's leader, Staff Sergeant Calvin Gibbs, then allegedly threw a grenade at the man while an order was given for him to be shot.

Afterwards, Gibbs is described cutting off one of the man's little fingers and removing a tooth.

The patrol team later claimed to their superiors that the mullah had tried to threaten them with a grenade and that they had no choice but to shoot.

On Sunday night many organisations employing foreign staff, including the United Nations, ordered their staff into a "lockdown", banning all movements around Kabul and requiring people to remain in their compounds.

In addition to the threat from the publication of the photographs, security has been heightened amid fears the Taliban may try to attack Persian new year celebrations.

There could also be attacks because Hamid Karzai, the Afghan president, is due to make a speech declaring which areas of the country should be transferred from international to Afghan control in the coming months.

One security manager for the US company DynCorp sent an email to clients warning that publication of the photos was likely "to incite the local population" as the "severity of the incidents to be revealed are graphic and extreme".