Police in London said Friday they had arrested four men in connection with an alleged extremist plot, which media reports said was planned for British soil.

Police in London said Friday they had arrested four men in connection with an alleged extremist plot, which media reports said was planned for British soil.

The men, aged 19, 22, 25 and 27, were arrested overnight "on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism", Scotland Yard said.

A number of addresses and vehicles are being searched as part of the investigation, which is being carried out in cooperation with the domestic intelligence agency MI5.

"These arrests and searches are part of an ongoing investigation into extremist-related terrorism," it said.

Media reports said the men were accused of plotting an attack in Britain.

There was no current indication of a link to Syria or the ISIL group, the BBC added.

Three suspects were detained at addresses in west London and High Wycombe, west of the capital. Armed officers were present at two arrests but no shots were fired, police said.

The eldest suspect was arrested in a car in west London, again by armed officers. All four remain in custody in police stations in central London, the statement said.