LONDON — The police in Britain said that they had arrested five men under anti-terrorism laws near the Sellafield nuclear site in the north of England.

The men were stopped in a vehicle “close to the site? on the Irish Sea coast on Monday afternoon according to a statement from West Cumbria police. All are aged in their 20s, the statement said, and all are from London.

They were arrested under a provision of Britain’s terrorism laws that allows suspects to be questioned without charge, police said, and have now been handed over to the specialist North West Counter Terrorism Unit in Manchester.

A BBC report suggested the men were of Bangladeshi origin and that they were thought to have been filming near the site.

A spokeswoman for the unit, which works closely with Britain’s domestic intelligence service, MI5, declined to confirm the report or provide further details because “the investigation is at an early stage,? and questioning is under way.

But she did say that there is “no link at this stage? to the death of Osama bin Laden in Pakistan, an event which prompted Islamic extremists to warn that Britain will be a target for retaliatory attacks. British authorities have told the public to be alert on public transportation and in other venues.