The Afghan Government has pledged it will get to the bottom of controversial reports that Taleban prisoners who died in custody are buried in a mass grave in the north of the country.

We need to find out exactly who was behind this, and for what reason this happened

Omar Samad Foreign ministry

The men are said to have suffocated while being transported in airtight containers from the town of Kunduz, where they had surrendered to Northern Alliance forces, to a prison at Sheberghan.

The mass grave is near Sheberghan.

An Afghan foreign ministry spokesman, Omar Samad, told the BBC's World Today programme that the government would find out who was responsible - even if it was someone who had subsequently joined the administration.

"We need to find out exactly who was behind this, and for what reason this happened," he said.

"There are a lot of questions that need to be answered."

He added that the government was committed to a full inquiry, and had asked outside agencies for help in this.

The controversy has drawn attention to the role of US special forces, who were co-ordinating efforts between the Northern Alliance commander in the area, General Abdul Rashid Dostum, and the American military.

The prisoners were being held by forces loyal to General Dostum.

Red Cross concerns

The Pentagon has said that the International Committee for the Red Cross was in charge of overseeing the transport of Taleban prisoners of war.

An ICRC spokesman in Geneva, Eros Bosisio, told the World Today that interviews with Taleban prisoners at Sheberghan had raised concerns about the way prisoners were being transported.

A United Nations team, which identified the grave, confirmed that suffocation was the cause of death in the cases of three bodies they exhumed.

The UN has said its staff will keep an eye on the site to ensure it is not tampered with before any investigation.