At least 16 detainees at the largest and maximum security Welikada prison and two in the north-central Anuradhapura prison are on hunger strike since yesterday, prison officials said today.
The detainees allege that Sri Lankan authorities have held them over a long period of time without any charge. Most have been imprisoned on suspicion of links with the Tamil Tigers.
The detainees are usually being held under the Prevention of Terrorism Act (PTA), which allows security forces to detain people for up to 18 months without presenting them before a court.
UN's human rights chief Zeid Ra'ad al-Hussein, who visited the country early this month, has said in a landmark report last September that the government had acknowledged holding 258 men and women under the PTA but only 54 of them had been convicted of anything.
Following an intervention by President Maithripala Sirisena, some of those detained have been released.
Tamil rights groups, however, call for a blanket amnesty to all those held for having suspected links with Liberation Tigers of Tamil Eelam (LTTE).
Northern Province's Chief Minister CV Wigneswaran has urged Hussein to seek their release through a blanket amnesty.
Nearly 30 prisoners of varied ethnicities died in prisons during rioting in 2012.
