Two prisoners who died while being held for interrogation at the US military base in Afghanistan had apparently been beaten, according to a military pathologist's report. A criminal investigation is now under way into the deaths which have both been classified as homicides.

 

The deaths have led to calls for an inquiry into what interrogation techniques are being used at the base where it is believed the al-Qaida leader, Khalid Sheikh Mohammed, is now also being held. Former prisoners at the base claim that detainees are chained to the ceiling, shackled so tightly that the blood flow stops, kept naked and hooded and kicked to keep them awake for days on end.

 

The two men, both Afghans, died last December at the US forces base in Bagram, north of Kabul, where prisoners have been held for questioning. The autopsies found they had suffered "blunt force injuries" and classified both deaths as homicides.

 

A spokesman for the Pentagon said yesterday it was not possible to discuss the details of the case because of the proceeding investigation. If the investigation finds that the prisoners had been unlawfully killed during interrogation, it could lead to both civil and military prosecutions. He added that it was not clear whether only US personnel had had access to the men.

 

One of the dead prisoners, known only as Dilawar, died as a result of "blunt force injuries to lower extremities complicating coronary artery disease", according to the death certificate signed by Major Elizabeth Rouse, a pathologist with the Washington-based Armed Forces Institute of Pathology, which operates under the auspices of the defence department. The dead man was aged 22 and was a farmer and part-time taxi-driver. He was said to have had an advanced heart condition and blocked arteries.

 

Chris Kelly, a spokesman for the institute, said yesterday that their pathologists were involved in all cases on military bases where there were unusual or suspicious deaths. He was not aware of any other homicides of prisoners held since September 11. He said that the definition of homicide was "death

 

resulting from the intentional or grossly reckless behaviour of another person or persons" but could also encompass "self-defence or justifiable killings".

 

The death certificates for the men have four boxes on them giving choices of "natural, accident, suicide, homicide". The Pentagon said yesterday that the choice of "homicide" did not necessarily mean that the dead person had been unlawfully killed. There was no box which would indicate that a pathologist was uncertain how a person had died.

 

It is believed that Khalid Sheikh Mohammed, described as the number three in al-Qaida, is being interrogated at Bagram. He is said to have started providing information about the possible whereabouts of Osama bin Laden whom he is said to have met in Pakistan last month. Most al-Qaida suspects are being held outside the US which means that they are not entitled to access to the US judicial system.

 

Two former prisoners at the base, Abdul Jabar and Hakkim Shah, told the New York Times this week that they recalled seeing Dilawar at Bagram. They said that they had been kept naked, hooded and shackled and were deprived of sleep for days on end. Mr Shah said that American guards kicked him to stop him falling asleep and that on one occasion he had been kicked by a woman interrogator, while her male colleague held him in a kneeling position.

 

The commander of the coalition forces in Afghanistan, General Daniel McNeill, said that prisoners were made to stand for long periods but he denied that they were chained to the ceiling. "Our interrogation techniques are adapted," he said.

 

"They are in accordance with what is generally accepted as interrogation techniques, and if incidental to the due course of this investigation, we find things that need to be changed, we will certainly change them."

 

In January, in his state of the union address, President George Bush announced that "3,000 suspected terrorists have been arrested in many countries" and "many others have met a different fate" and "are no longer a problem to the United States".

 

The other death being investigated is that of Mullah Habibullah, the brother of a former Taliban commander. His death certificate indicates that he died of a pulmonary embolism, or a blood clot in the lung.