Colombo: At least 21 Sri Lankan fishermen have been detained by the Indian authorities after they entered into the country's waters at Minicoy and Andaman islands, officials said on Wednesday.

Eleven fishermen were apprehended for allegedly fishing in the Andaman island and 10 others were nabbed when they entered the Indian waters at Minico island while escaping from sea pirates, Sri Lankan Ministry of Fisheries was quoted as saying.

Illegal fishing on each other's waters is a frequent occurrence among fishermen of both the nations.

The issue has become a centre of diplomatic activity between the two countries since January this year.

Sri Lankan Navy was accused of killing at least two Indian fishermen.