The European Union (EU) anti-piracy Naval Force has said that pirates off the coast of Somalia who hijacked an oil tanker with Eight Sri Lankan crew on board are demanding a ransom for the release of the vessel.

According to Ceoafrica, the EU force said it had made contact by phone with the ship's master, who said his vessel and crew were being held captive in an anchorage off the north coast in the semi-autonomous region of Puntland.

But the statement gave no details on the size of the ransom.

The ARIS-13 was en route from Djibouti to the Somali capital, Mogadishu, when it sent a distress signal, saying it was being approached by high-speed boats.

EU Navfor said as soon as it received an alert on the ship's seizure, it sent a patrol aircraft from its Djibouti base to try to make radio contact.

Its headquarters in London managed to contact the vessel's master by phone late on Tuesday.

A statement said “The master confirmed that armed men were on board his ship and they were demanding a ransom for the ship's release. The EU Naval Force has now passed the information regarding the incident to the ship's owners.

The armed men on board had earlier told a local official that they were fishermen whose equipment had been destroyed by illegal fishing vessels.