The international human rights group, Amnesty International, has accused the Sri Lankan army and a former Tamil militant group of secretly detaining eight civilians.

It said the civilians, some of them teenagers, disappeared in the northern Vavunia district during the past two months.

Amnesty called for their immediate release or transfer to proper places of detention.

Both the army and the Tamil group, the People's Liberation Organisation of Tamil Eelam, have denied the charge.

Amnesty says nearly six hundred people are still missing after being arrested by the army or the police in Sri Lanka.