NAIROBI, Kenya (AP) — Somali pirates seized a tanker carrying crude oil from Saudi Arabia to the United States in the increasingly dangerous waters off East Africa, an official said today, an attack that could pose a huge environmental or security threat to the region.

The Greek-owned Maran Centaurus was hijacked Sunday about 800 miles (1,300 kilometers) off the coast of Somalia, said Cmdr. John Harbour, a spokesman for the EU Naval Force. Harbour said there were 28 crew members on board the 300,000-ton ship.

Pirates have increased attacks on vessels off East Africa for the millions of dollars of ransom that can be had. Though pirates have successfully hijacked dozens of vessels the last several years, Sunday’s attack appears to be only the second ever on an oil tanker.

In November 2008, pirates hijacked the Saudi supertanker Sirius Star, which held 2 million barrels of oil valued at about $100 million. The tanker was released last January for a reported $3 million ransom after a two-month drama.

 that helped galvanize international efforts to fight piracy off Africa’s coast.

Somalia’s lawless 1,880-mile (3,000-kilometer) coastline provides a perfect haven for pirates to prey on ships heading for the Gulf of Aden, one of the world’s busiest shipping routes.