Somaliland President Dahir Rayale Kahin has sent a letter of complaint to his Yemeni counterpart but has not yet received a reply, its fisheries ministry said.

The self-declared republic broke away from Somalia when the country plunged into anarchy 15 years ago but is not recognised internationally. Though the northwestern territory is relatively peaceful and stable, its campaign for recognition has not convinced the outside world.

The fishermen from Yemen, across the Gulf of Aden, were due to go on trial later on Sunday in the port town of Berbera.

"We have information that more than 200 Yemeni boats illegally fish in our territorial waters," Coast Guard Commander Jibril Hagar said.

"We have seized nine fishing boats in our first campaign to free our territorial waters from illegal foreign fishing. Three other boats managed to escape due to some technical failure in our fast boats," he added.

Interior Minister Mohamed Aden Mire stressed the difficulties in safeguarding Somaliland's long coastline from illegal fishing as well as smuggling.

"It can be used by terrorists and pirates as well and so we are trying to build and modernise our coastal guards," he said