A Scot was today named as one of two British hostages captured when pirates hijacked the supertanker Sirius Star.

The families of James Grady, from Strathclyde and Peter French, from County Durham - the two Britons in the hijacked crew - said today they hoped they would be home safely very soon.

Foreign Secretary David Miliband called for the immediate release of the hijacked crew of a giant oil tanker after the vessel anchored off the coast of Somalia.

Mr Miliband said the problem of piracy was "a grave danger to the stability in the region".

His remarks came as it emerged pirates had captured two other vessels in separate incidents - bringing the number of ships seized in the area to eight in the past two weeks.

Speaking to the BBC as he arrived in Beirut for talks with the Lebanese government, Mr Miliband said: "The United Kingdom is very worried about the piracy in the Gulf of Aden and in Somalia.

"We call on those holding the Britons to release them and the rest of the crew immediately."

He said the Royal Navy was involved in efforts to resolve the situation. The captive Britons are vessel's the chief engineer and second officer.

"The Royal Navy is coordinating the European response as well as contributing to the international mission there.

"Obviously, the problem of piracy around Somalia is a grave danger to the stability in the region."

Earlier, Armed Forces Minister Bob Ainsworth said the seizure at the weekend of the fully-laden Sirius Star by pirates 420 nautical miles off the coast of Somalia was of deep concern.

"Alongside our international partners, Her Majesty's Government is deeply concerned, not least because two of the crew are British," Mr Ainsworth said, speaking from Kenya.

"Our thoughts are with the men and their families at this difficult time.

"We call on those holding the men to release them and the rest of the crew immediately."

His call came as the US Navy confirmed the vessel, carrying around two million barrels of oil, has anchored off the coast of Somalia near the city of Harardera.

The vessel's operator, Dubai-based Vela International Marine Ltd, said the 25 crew on board - two Britons, two Poles, one Croatian, one Saudi national and 19 Filipinos - were believed to be safe.

A statement from the president of Vela International Marine Ltd, Salah Kaaki, said: "Our first and foremost priority is ensuring the safety of the crew.

"We are in communication with their families and are working towards their safe and speedy return.

"Vela continues to monitor the situation and co-ordinate with the relevant embassies at this time. Vela is awaiting further contact from the pirates in control of the vessel.

"In view of the sensitive nature of this matter and in the interests of the safety of the crew on board, Vela will make no further public comments on this incident until further notice."

The large oil tanker is owned by Saudi oil company Aramco but was sailing under a Liberian flag.

It is 1,080ft (330m) long and can carry about two million barrels of oil.

The hijack, which was the first successful attack so far out at sea, raises fears that international patrols nearer the coast and in the Gulf of Aden will not be enough to protect vital trade routes as pirate gangs become ever more audacious.

Yesterday, it was reported that pirates had hijacked a Thai fishing boat with 16 crew members and an Iranian cargo ship off the coast of Somalia.

The Rail, Maritime and Transport union, which represents seafarers, urged the Government to push for expansion of patrolling and escorts to help counter the threat of piracy.

General secretary Bob Crow said: "The growth of piracy is a threat faced by the shipping industry on a global scale and it requires a global response.

"The most important immediate task is to get the Sirius Star, and the many other vessels already being held by pirates, released with their crews unharmed.

"Like all workers, seafarers should be able to work without the fear of imminent attack, and the ordeal faced by seafarers held to ransom is unimaginable.

"The scale of the problem is now so big that the Gulf of Aden, where so many seizures have taken place, is known among mariners as the 'gates of hell'.

"One problem is that some ship owners, particularly those flying flags of convenience, will gamble with their crews' safety by taking short cuts outside the patrolled safe zone."

Saudi Foreign Minister Prince Saud, speaking in Athens, called the hijacking "an outrageous act".

He added: "Piracy, like terrorism, is a disease which is against everybody, and everybody must address it together."

Spokesmen for both Nato and the US Navy said they did not have any plans to intercept the ship.

Cyrus Mody, manager of the International Maritime Bureau - a specialised division of the International Chamber of Commerce - said it was very difficult for security patrols to intervene once a ship had been boarded.

"Once the pirates are on a vessel, you have the risk of the crew being used as human shields or being injured in crossfire.

"There could also be damage to the ship's cargo and very often they carry a mixed cargo - some hazardous, some not - so it is a very difficult judgment call."

The renewed fears about piracy came as it was announced today that eight suspected Somali pirates were handed over to the Kenyan authorities by the Royal Navy following an attempted hijacking in the Gulf of Aden last week.

Downing Street said Britain was involved in the anti-piracy effort in the region, with the Royal Navy frigate HMS Cumberland operating as part of the Nato maritime taskforce.

The Prime Minister's spokesman said the Government was committed to legislation strengthening the powers of the Armed Forces to intervene against pirates.

"We have ensured that the Navy has the means and the authority to disrupt acts of piracy," the spokesman said.

Today the Indian navy said one of its warships dedicated to fighting pirates had successfully fought off an attempted pirate attack in the Gulf of Aden.

An official statement said a suspected pirate ship with two speed boats in tow approached the INS Tabar yesterday, threatened to blow up the warship, and opened fire.

Indian naval officers saw well-armed men roaming the ship's deck, according to reports.