Afghan police dug out the body of the UN World Food Programme worker on Wednesday, two days after he was murdered, Deputy Governor Sayed Ahmad Sayyid of Faryab province said.

Four people have been arrested over the killing in Maymana, the capital of north western Faryab province, he added.

He said that all four were believed to have been killed by theives.

World Food Programme spokesman Maarten Roest said the murder was a "very regrettable event" and the organisation was saddened by the loss of a staff member.

But he added that the attack was understood to be unrelated to his work with the aid agency.

Faryab, 400km northwest of Kabul, is one of the powerbases of Uzbek commander general Abd al-Rashid Dostum, who escaped an assassination attempt last month.