ATHENS - A Greek-owned oil tanker was seized by Somali pirates off Oman's coasts, Greek media reported Friday, citing Greek Coast Guard and the vessel's management sources.

According to perliminary information, the Liberian-flagged SMYRNI with a 17-member crew on board was attacked by pirates some 300 nautical miles east of Oman.

Sources with Dynacom Tankers Management, its management operator, said the vessel was transporting about 135,000 metric tones of oil from Turkey and was now heading to Somalia.

The attack was the first major blow Somali pirates have struck against the international maritime industry in months.

The deployment of the international anti-piracy task forces at the Arabian Sea over the past few years to safeguard the sea routes of merchant ships has reduced the number of pirate attacks. But the pirates still hold some dozens of ships and hundreds of hostages.

Pirates have extracted millions of US dollars in ransoms from shipping companies in exchange for releasing the vessels and crews.