Tamil Nadu Chief Minister J. Jayalalithaa Thursday asked Prime Minister Manmohan Singh to step up efforts to secure the release of 53 Indian fishermen who were arrested by the Sri Lankan naval force.

"We are agitated by incidents of repeated capture of our fishermen while pursuing their livelihood. We expect the government of India to also respond and react pro-actively when incidents of this nature happen," Jayalalithaa told the prime minister in a letter, which was released here.

Sri Lankan authorities arrested 19 fishermen Wednesday and another 34 Thursday for allegedly fishing in Sri Lanka's waters.

"Let Sri Lanka not be emboldened by your silence and construe it as a sign of weakness and indifference towards our fishermen," she said.

Jayalalithaa also urged Manmohan Singh to summon the Lankan high commissioner in New Delhi and lodge a strong protest against the continuing arrests and incidents of violence against Indian fishermen.

She recalled the pending case in the Supreme Court filed by Tamil Nadu challenging the unilateral withdrawal of the international maritime boundary line (IMBL) leading to the ceding of Katchatheevu islet to Sri Lanka.

"You will agree with me that solutions to the fishing disputes between two neighbouring countries are not resolved by force or by treating the fishermen of the neighbouring country as 'criminals' and arresting and terrorising them through assaults and gun firing," she said.

According to her, the increasing belligerence of Sri Lanka in the recent past towards the Indian fishing boats fishing in their traditional fishing areas, as exhibited by a spurt of arrests and violence, is a worrisome trend, the chief minister said.