Five men have been arrested under anti-terrorism laws near a nuclear waste-processing plant in northwest England, police said Tuesday.
Cumbria Constabulary said the men were detained under the Terrorism Act near the Sellafield plant on Monday after officers from the Civil Nuclear Constabulary stopped a car.
All are from London and in their 20s. They were being held a police station in Manchester, home to the North West Counter Terrorism Unit.
Police would not confirm media reports that the men were of south Asian origin and had been taking photographs. They were arrested under Section 41 of the Terrorism Act, which allows police to detain anyone they "reasonably suspect" of being a terrorist.
Prime Minister David Cameron has said Britain should be extra-vigilant against terrorism in the coming weeks following the death of Osama bin Laden.
Greater Manchester Police said the investigation was in its early stages, but the force was "not aware of any connection to recent events in Pakistan."
Sellafield, about 250 miles (400 kilometers) northwest of London, was the site of Britain's first nuclear power plant, which operated between 1956 and 2003. It now reprocesses nuclear waste and produces nuclear fuel.