Windhoek  - A Namibian rights group said Tuesday it believed it may have discovered nine graves containing the remains of hundreds of alleged victims of a past state security crackdown on the northern border with Angola.

Namibia's National Society for Human Rights (NSHR) said it had been alerted to the presence of what appeared to be unmarked graves on either side of the border by various sources since the beginning of 2007. It said its sources included ordinary citizens, and present and former members of the Namibian police and army.

The society said members of the Angolan police had confirmed the presence of "no name mass graves" in the area that extends up to 30 kilometres into southern Angola, as recently as July.

In a report entitled Namibia Enforced Disappearances: Discovery of 'No Name' Gravesites, the NSHR said it was investigating reports of two mass graves allegedly containing between 1,000 and 1,600 people.

The report cited unnamed sources as estimating up to 90 bodies were buried in a further seven sites.

"In the absence of any forensic investigation, we have no absolute proof that these are, indeed, mass gravesites," the NSHR stressed.

But the society also claimed it had "reasonable cause" to believe that the victims whose remains were allegedly buried in the graves were victims of alleged enforced disappearances carried out by state forces between 1994 and 2003.

The society referred to a presidential decree issued by then Namibian president Sam Nujoma ordering the security forces to crack down on all infiltrations from Angola in the north-eastern Kavango and Caprivi regions.

At the time the Angolan UNITA rebel movement, which was fighting a civil war with Angola's ruling party, was using the area as a hideout.

The NSHR called for an independent forensic investigation to locate remains at the sites and recommended that former president Nujoma be held accountable for any human rights violations that came to light.

Contacted for reaction, a spokesman for Nujoma told Deutsche Presse-Agentur dpa "this is an old story" and that the NSHR was "just trying to discredit the former president."

The government of President Hifikepunye Pohamba had yet to react to the allegations.

This would not be the first finding of mass graves in Namibia, if confirmed. Graves containing victims of the country's liberation war from apartheid South Africa were found in the north in 2005.

The NSHR said the latest discovery was probably unrelated to the liberation war. (dpa)