KHARTOUM (AFP) - Government doctors in Sudan amputated a man's hand and foot to carry out a sentence for robbery, rights groups said on Wednesday, describing the extremely rare punishment as a form of torture.

The amputation of Adam al-Muthna's right hand and left foot took place by court order at the interior ministry's Al-Rebat hospital in Khartoum on Feb 14, the rights groups said, citing "reliable sources."

Muthna, 30, was convicted of armed robbery related to an attack on a truck carrying passengers, said a statement issued by New York-based Human Rights Watch, also on behalf of the African Centre for Justice and Peace Studies, London-based Redress and US-based Physicians for Human Rights.

"Cross amputation is a form of state-sponsored torture," said Vincent Iacopino, senior medical adviser at Physicians for Human Rights.

Sentences of amputation have previously been handed down under Islamic syriah law, whose introduction in 1983 sparked a devastating 22-year civil war.

But since 2001 there have been no known cases of such sentences being carried out, the rights groups said.

The Sudanese authorities "routinely" order flogging penalties and last year issued two sentences of death by stoning for adultery, although the capital punishment was later overturned, they added.

"Authorities should immediately stop imposing such cruel and inhuman punishments, and bring laws in line with Sudan's human rights obligations," said Mr Daniel Bekele, Africa director at Human Rights Watch.