An eighth individual whose identity has not been determined was also swept up in arrests tied to alleged plots against an unnamed facility and commission of a “terrorist act.”

London police have arrested seven Iranian nationals and another individual whose nationality was not yet identified in two unrelated counter-terrorism investigations.

The first set of arrests of five people were for “suspicion of preparation of a terrorist act” to be conducted against an unnamed but specific locale. Police said they are communicating with the “affected site” to provide support.

The five individuals, four of them between the ages of 29 and 46, were arrested in Swindon, west London, Stockport, Rochdale and the Manchester area. Searches are being conducted at addresses in those locations. All five men currently remain in police custody.

“The investigation is still in its early stages and we are exploring various lines of enquiry to establish any potential motivation as well as to identify whether there may be any further risk to the public linked to this matter,” London Counterterrorism Commander Dominic Murphy said.

Counterterrorism police arrested a second set of three Iranian nationals, aged 39 to 55, on Saturday, at locations in northwest London and west London.

The men were detained under Section 27 of the National Security Act, which allows them to be held for suspicion of “espionage, sabotage, and persons acting for foreign powers.” Searches are being conducted at the three addresses where they were picked up.

The investigation is being led by the Met’s Counterterrorism Command with the assistance of local officers from the areas.

British Home Secretary Yvette Cooper praised the forces on Sunday.

Protecting national security is the first duty of government and our police and security services have our strong support in their vital work,” she said. “These are serious events that demonstrate the ongoing requirement to adapt our response to national security threats.”