Oceans Beyond Piracy, a privately funded and independent non-profit organization, announced late Thursday on its Twitter account that pirated Aris 13 oil tanker is now free and the crew are safe.

John Steed, a former British army officer with the NGO, also confirmed the release and said the ship is proceeding to Bossaso, a port city in the Bari region of Puntland state in northeastern Somalia.

Pirates on Monday hijacked an oil tanker with eight crew from Sri Lanka off the coast of Somalia, the first hijacking of a large merchant vessel by Somali pirates since 2012.

Local media said the release occurred after negotiations by local elders and officials with the pirates. The details of the negotiations could not be disclosed yet.

Earlier Thursday, fighting broke out between Puntland anti-pirate forces and armed pirates.

The hijacking came against a backdrop of reduced piracy activities in Somalia.