A group of men recently arrested in Britain had been planning an attack, officials said, a development likely to ramp up tensions between Israel and Iran.

British counterterrorism officers have arrested several Iranian men over an alleged plot to attack an unspecified target in London.

Iran has “categorically” denied any involvement after a terror plot involving alleged Iranian men, including one from Swindon, was foiled.

Five Iranians suspected of plotting an attack on the Israeli embassy in London belong to a highly trained special operations unit, a former intelligence officer has suggested. The group who were arrested on suspicion of preparing an act of terrorism allegedly belong to Unit 840,