Somali 'pirates' who hijacked the Sri-Lankan-flagged oil tanker Aris 13 in the Indian Ocean on Monday (13 March), have demanded compensation over illegal fishing as they are still holding captive the crew of eight.

In the first hijack of a commercial ship by Somali pirates since 2012, the freighter turned off its tracking system and diverted its course towards the Somali coast after sending a distress call, John Steed of aid group Oceans Beyond Piracy was quoted as saying by Reuters.

Eight crew members, who were reportedly on board the tanker at the time of the hijack, are still held on the vessel, AFP news agency reported on Tuesday (14 March).

The attackers are demanding compensation for a rise in illegal fishing in Somali waters, according to one of the hijackers quoted by Voice of America's Somali service.

One of the hijackers said that they are fishermen and not pirates. "We have decided, as local fishermen, to resist illegal fishing. We have taken arms to defend ourselves, and we will continue," the man said.

While it is unclear how much the fishermen are demanding in compensation, they confirmed the ship's crew are healthy and taken care of. "It's not our principle to kill them. They are healthy. We looked after them. We are after the people who sent them, to make sure they never return".

The Aris 13 is owned by Panama company Armi Shipping, managed by Aurora Ship Management in the United Arab Emirates, according to Reuters.