Police in London, England, said officers arrested four men on Friday on suspicion of aiding Iran by spying on the Jewish community.

Metropolitan police said one Iranian and three dual British-Iranian nationals ages 22 to 55 were arrested in and around north London shortly after 1 a.m. Friday as part of a Counter Terrorism Policing investigation. The men are accused of spying on locations and individuals to assist Iran’s foreign intelligence system.

Searches remain active on Friday at the arrest locations and nearby properties.

“We understand the public may be concerned, in particular the Jewish community, and as always, I would ask them to remain vigilant and if they see or hear anything that concerns them, then to contact us,” said Commander Helen Flanagan, who is in charge of counterterrorism policing in London.

Six more men were also arrested in Harrow, west London, on suspicion of assisting an offender, according to the police force.