Five men are being held under British anti-terror laws after they were arrested close to the Sellafield nuclear site.
The arrests were made after Prime Minister David Cameron urged Britain to remain vigilant against potential reprisals following the killing of al-Qaeda leader Osama bin Laden in Pakistan.
Police said they were unaware of any link between the arrests and Bin Laden's death.
The men were arrested yesterday after officers conducted a stop check on a vehicle near the Sellafield site in Cumbria.
The men are all aged in their 20s and from London.
A spokesman for the police's North West Counter Terrorism Unit declined to comment on media reports the men had been filming the site.
'There were suspicions from the Civil Nuclear Constabulary that led to some arrests. There were some suspicions about them near to the perimeter fence,' he said.
Police are holding the men under section 41 of the Terrorism Act, which allows officers to arrest people suspected of terrorist offences and hold them for 48 hours without charge.
The men were transferred to Manchester to be questioned by counter-terrorism officers.
The Sellafield site, in operation since the 1940s, includes a number of nuclear fuel reprocessing facilities and waste treatment plants.
