A defecting Russian spy has told “The Times” that his country’s secret service was responsible for the murder of six Red Cross nurses in a Chechen hospital 14 years ago.

The medical workers, a Spaniard, two Norwegians, a Canadian, a New Zealander and a Dutchman, were killed at a Red Cross hospital in an old school compound in Novye Atagi, south of Grozny. The murders took place in December 1996 and the crime has still not been solved. However, the Russian media has attributed it to Chechen fighters.

According to Major Aleksi Potyomkin, however, the Westerners were the victims of a Federal Security Service (FSB) special forces “search-and-destroy” unit that was breaking the terms of a newly negotiated truce ending the two-year war between Russia and Chechnya. Masked and heavily armed, they had engaged in a firefight with a group of Chechens before being ordered to enter the Red Cross hospital set up in an old school compound in Novye Atagi, south of Grozny.

How does Major Potyomkin know? Because he was there; a lieutenant at the time, in charge of protecting the rear of the column as it stalked through the snow. Now he is in hiding, with his wife and three small children, in a small town in Germany, trying to arrange his defection to one of two Western intelligence services.

The truth about the Novye Atagi killings is just one of the intelligence gifts that he has brought with him, backed up by a stolen FSB transcript of the radio traffic on that night. It is plainly intended as merely a taster: for the past seven years, Major Potyomkin has been part of a Russian undercover operation in Western Europe.

For him, and for the FSB -the successor to the Soviet KGB- the attack on the hospital was a blunder, a case of mistaken identity. Small beer in a dirty war.

“There was no inquiry about the operation, of course not,” said Major Potyomkin. “Why should the generals worry about a few dead foreigners when we had taken thousands upon thousands of casualties?”

A big man with a blond wisp of a beard, Major Potyomkin paused, perhaps to consider whether his words sounded callous to a foreigner. “Ultimately it was too expensive to punish us. They had invested a lot in our training, so everything was just buried.”

It could, however, be expensive now. If further investigation shows that this was a Russian atrocity, the families of the dead nurses would be within their rights to take legal action against Moscow.

Certainly, the relatives have been desperate for closure. The mystery surrounding the attack has dogged the Geneva based Red Cross for years.

Following the organisation’s principles of neutrality, its hospital guards were unarmed and the nurses, shot in their beds, had not so much as locked their room doors. “The murders were deeply shocking and traumatic,” said the Red Cross in a statement to The Times yesterday. “It has had a lasting impact.” The organisation maintains its operations in the North Caucasus, including Chechnya, and, it says, “is regularly seeking to clarify the circumstances behind the attack”.

The first assumption -that the attack was linked to an Arab warlord fighting on the Chechen side- proved to be a red herring. The commander, known as Khattab, had insisted that the Red Cross paint over their crosses, because they were associated with the Christian crusades – otherwise, he said, he would shell the hospital, even though it was already providing healthcare for hundreds of Chechens. The crosses were duly painted over, leaving no obvious culprit for the killings.

Major Potyomkin’s unit had been flown to Chechnya from Moscow shortly before the operation. “This is something that we could have left to military intelligence, except that we knew that they usually blew even the simplest of tasks,” he said, showing a flash of loyalty to the outfit that he is now deserting. “So we did it — and blew it, too, in our own special way.”

As he tells it, the mission was to destroy fighters, nicknamed borodatiye, or “beardies”. The unit split in two, with 14 men in the advance group under a Captain A. N. Sevastyanov (codename Trofim). Lieutenant Potyomkin (codename Blue Eye) was supposed to proceed about 700 metres behind, with two men, to cover their rear. He was 23 at the time, and not long out of FSB academy, and was using night-vision equipment. “I saw about twenty Chechen fighters coming across the fields, just ahead of us. It looked like they were carrying a ‘300’ towards the hospital.” (Ever since the Soviet invasion of Afghanistan, military slang for a wounded soldier has been “300”; for a corpse it is “200”. That was what used to be scrawled on crates carrying the tin coffins of Soviet soldiers back home.)

A firefight ensued. About a dozen of the Chechens were killed and the rest fled. The captain received the order to check the hospital. Lieutenant Potyomkin mounted the hill of a nearby cemetery -“graves are always good cover”- to give protecting fire as the other Russians stormed in. The commanders wanted the unit to smoke out any Chechen fighters hiding in the compound. If they made contact, the unit was told, they were to “sort it out on the spot, in the usual way”.

Then, according to Major Potyomkin, everything went wrong. Captain Sevastyanov radioed out a desperate message to his commanders; the gist of which was that the targets they had encountered within were not “ghosts” after all — the slang term for Chechen fighters. “No beardies – only foreigners!” he cried.

When the shooting stopped the unit scattered captured Chechen IDs around the compound to make it look like a Chechen attack. The FSB men withdrew, flying straight back to Moscow and leaving mayhem behind them.

For the Red Cross, it was a terrible violation and prompted soul searching about whether they should arrange armed guards in certain combat zones. It was the moment when international organisations across Chechnya pulled out, fearing for their staff. The war, technically over, was still being fought – but without rules.

Not everything adds up in the defector’s account, it must be said. The rapid progress of the FSB men through the corridors of the hospital; shooting the nurses at point-blank range; the convenient availability of the Chechen IDs – as even Major Potyomkin admits, it smacks of a planned attack.

“Maybe the advance unit had been separately briefed, I don’t know. All I do know is that it has always a been central principle in FSB special units: if someone sees you, eliminate them. No witnesses.”

Whatever the motives, it seems clear: Russia has a case to answer.

As of last night, the FSB had not responded to the allegations.

From the transcript: how the attack unfolded

“Centre, Centre! Screw it! Blue Eye — provide cover! We’ve got problems, we’re coming out. We’ve got a 300”
It is Trofim speaking, trying to get new orders. A “300” is slang for a wounded soldier

“Centre! Shit, they aren’t ghosts at all in the school!”
Ghosts is slang for Chechen fighters

“We’ve got a f***ing 300. Centre, what kind of balls-up is this? They weren’t Russian at all in there! Who was that? No beardies, only foreigners. They have 200s [dead], three of them for sure . . . did you understand me?”

The commander replies: “Have you stopped being able to distinguish Chechens from people? Have you got the Chekhs’ documents with you? Chuck some of them out. In the settlement — did you understand me?”

Trofim answers: “I get it, Centre. We’ll do it”