Dassanayake said the incident took place in Sri Lankan waters and away from international shipping lanes.


"We repeatedly tried to check the identity of the vessel, but neither will it give one, nor will it stop forcing us to take action," Brigadier Prasad Samarasinghe, a military spokesman, said of the incident near Matara.

"Our people are hearing the loud sound of explosions, suggesting the ship was carrying explosives or other warlike materials," Samarasinghe said.  

The incident comes a day after the Tamil Tigers slightly injured the Italian and US ambassadors and United Nations representative to Sri Lanka when they shelled a delegation of diplomats led by the island's human rights minister to the restive east.