COLOMBO: Sri Lanka's navy Tuesday said it had arrested 21 Indian fishermen after a confrontation with two trawlers poaching in the island's territorial waters.

A fast attack craft was damaged in the clashes on Monday night, the navy said in a statement, without giving further details.

"As the Indian trawlers were attempting to evade naval units with their aggressive manoeuvres, they also caused damages to the SLN Fast Attack Craft," the statement said.

It did not say if there were casualties, but said the navy seized equipment used by the Indians for "bottom-trawling", a fishing method banned in Sri Lanka that snares maritime creatures on the ocean floor.

Indian fishermen are known to stray into Sri Lankan waters along the Palk Strait, a narrow strip of sea separating the two South Asian neighbours in the Indian Ocean.

Last week, a Sri Lankan court freed 56 Indian fishermen who had faced poaching charges, but retained their boats.