By Frances Harrison BBC correspondent in Colombo

More than 130 Tamil prisoners in southern Sri Lanka have called off their nine-day-old hunger strike after receiving assurances that conditions will improve within the next month.

Prisoners in Kalutara Jail were visited by government ministers, Tamil parliamentarians and a Catholic Bishop - but journalists were not allowed access.

The health of the prisoners was beginning to deteriorate seriously with some being admitted to hospital.

The Catholic Bishop of Mannar, Rayappu Joseph, who visited the inmates, said they were very weak, but some plucked up the courage to speak to the government delegation that visited them for several hours of negotiations.

Government visit

The prisoners have been calling for their cases to be heard by the courts, and for the charges to be dropped if insufficient evidence is available.

Tiger rebel hugs a member of family after being reunited

They agreed to suspend their hunger strike on condition a senior government minister would visit them again in a month's time to check if their situation had indeed improved.

The prisoners at Kalutara jail are among 220 people the government says are still detained under the Prevention of Terrorism Act - a law that is no longer being used according to the current cease-fire agreement with Tamil Tiger rebels.

Human rights

In recent months, hundreds of people detained under anti-terrorism laws have been released after the cases against them were dropped.

Tamil parliamentarian R Sambanthan said it was very important that these remaining prisoners be released because many Tamils who had been involved in the armed struggle for years were now enjoying freedom - as were security force personnel alleged to have committed human rights violations.

Human rights lawyers have alleged the anti-terrorism act has been misused in the past to arrest Tamils, many of whom it is thought had nothing to do with the Tamil rebels.

It is not clear how many people in all have been detained under this controversial law - and exactly how many of them have now been released because of the ongoing peace process.