At least 38 Indian fishermen lodged in Sri Lanka's Jaffna prison for alleged poaching are on a fast unto death demanding their early release.

The Indian consulate office in Jaffna has alerted the Indian High Commission officials after the Indian prisoners began their protest in the jail, prison officials said.

The fishermen were arrested for poaching in Sri Lankan waters.

Last month, Sri Lanka released 5 Indian fishermen, who had been sentenced to death on drug trafficking charges, after a presidential pardon from Mahinda Rajapaksa.