Pirates fired guns and rocket-propelled grenades at a liquefied natural gas tanker off the coast of Oman on Wednesday, and three shots hit the vessel, the International Maritime Bureau's anti-crime arm said.

'Pirates in a dhow armed with guns and RPG fired upon a LNG tanker under way. The dhow closed to 50 metres from the ship and fired shots, of which three hit the vessel,' the IMB said in a report.

LNG industry sources said on Thursday the LNG Aries, managed by Japan's Mitsui O.S.K. Lines, was the victim of the attack, but the company was not available for immediate comment on the condition of the ship.

The IMB said the ship was not boarded by the pirates but did not say whether it was hit by grenades.

Although relatively low-lying crude oil tankers have been targets of piracy and at least one has been hijacked, so far no high-sided LNG tankers are known to have been taken.

Ship tracking data on Reuters show the 126,750 cubic metre capacity tanker, which left Spain for the Middle East in early June, was sailing back towards the Suez Canal on Thursday.-Reuters