LONDON - BRITISH Foreign Secretary David Miliband warned of the 'grave danger' of piracy in Somalia on Wednesday, calling for the immediate release of crew members including Britons hijacked on a Saudi supertanker.

'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 told the BBC in Beirut, where he was holding talks with the Lebanese government.

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

The Foreign Office says the chief engineer and second officer on the Sirius Star ? hijacked by pirates off the east African coast in the Indian Ocean Saturday ? are both British.

The supertanker is carrying US$100 million (S$1 of Saudi oil and is now at anchor off Puntland, a breakaway northern state in Somalia.