Somali pirates seized control of an oil-laden Russian tanker in the Gulf of Aden early on Wednesday, setting up a high-seas standoff with a Russian destroyer steaming to the zone.
The 230-metre (755 foot)-long Moscow University was heading east from the Gulf of Aden early Wednesday when it was boarded by pirates around 350 nautical miles off the Yemeni coast, the EU anti-piracy mission said.
The ship's Russian operator said the tanker had been on its way to China from the Red Sea with 86,000 tonnes of crude oil, believed to be worth around 50 million dollars.
A large anti-submarine ship, the Marshal Shaposhnikov, had been sent to the zone. The warship, part of the Russian fleet engaged in the EU's anti-piracy mission NAVFOR, has two helicopters and an infantry unit on board.
The 23 all-Russian crew of the Moscow University were unharmed, the ship's operators Novoship said.
"According to the latest information received from the master none of the 23 seafarers on board have been hurt, the vessel and the cargo sustained no damage," said Novoship, adding that communications with the vessel had been cut at 0450 GMT.
It said the attack began around 50 minutes earlier when the pirates opened fire and tried to board the vessel. The captain managed to inform naval forces in the region before his radio was silenced.
A EUNAVFOR commander, Read Admiral Jan Thornqvist, said in the Kenyan port of Mombasa that the tanker was "hijacked approximately 350 nautical miles east of Socatra," the Yemeni island in the Gulf of Aden, as it cruised east for China.
Thornqvist said the vessel "was attacked by just one skiff" whose occupants managed to scale the sides of the tanker. The crew had been locked into a cabin as the pirates took control.
NAVFOR said the tanker had not registered with the Maritime Security Center Horn of Africa for its transit through the Gulf of Aden.
The seizure of the Moscow University is a jolt to the international anti-piracy system put in place along one of the world's busiest shipping routes.
The International Maritime Bureau (IMB) said recently the presence of numerous foreign warships in the Gulf was proving an effective deterrent, with 17 attacks there in the first quarter of 2010, down from 41 a year earlier.
The capture of the 106,000 tonne tanker immediately drew comparisons with the Sirius Star, a larger tanker which was carrying a full load of two million barrels of crude oil when it was hijacked in November 2008.
It was taken to the pirate lair of Harardhere on the Somali coast and held for two months before being released for a reported ransom of three million dollars.
In a separate incident Wednesday, a 40,000-tonne South Korean-flagged cargo ship, the Ocean Trader, escaped an attack by pirates just hours after the seizure of the tanker.
"The ship ... managed to evade the attack and all personnel are reported to be well," NAVFOR spokesman John Harbour said.
The attempted attack took place in the Indian Ocean, some 200 nautical miles north-west of the Comoros archipelago.