BOSASO, SOMALIA (Reuters) - A huge explosion was heard from a ship off the coast of Somalia's Puntland region late on Monday (June 26) and flame was seen rising from what was possibly a foreign naval vessel, an official told Reuters.

"We heard (a) huge explosion and flame rising from the ship. I believe that the ship is foreign," Ali Shire, mayor of Puntland's port town of Alula, a pirate haven, told Reuters on Tuesday.

He said he believed the ship was likely a naval vessel because two foreign navy ships had helped rescue the crew.

It was not immediately clear whether the explosion was caused by an accident onboard the vessel or was triggered by pirate attackers. It was also not clear whether the vessel had sunk after the blast.

Somali pirates often prowl waters around Alula. In March, pirates hijacked an oil tanker, Aris 13, with eight Sri Lankan crew on board, the first time a commercial ship was commandeered in the region since 2012.