The head of Britain’s domestic intelligence service MI5, Ken McCallum, said Russia remained “aggressor number one” and that the agency’s terrorism and state-threats operational missions are now of pretty much equal scale, according to BBC News.

He said MI5 had made over 50 arrests in the last year over Iran-linked activities. McCallum also said Iran is trying to hit military sites in the UK and that the suspected plot to attack a US-run military air base in September is “not unique”, according to ABC News, in a story distributed by The Associated Press (AP).