Britain lifted its national security threat level to critical from severe on Friday (September 15), meaning an attack is expected, after a bomb on a London commuter train injured 29 people.
Prime Minister Theresa May said in a televised statement that armed police and members of the military would be seen on the streets in the coming days.
“For this period, military personnel will replace police officers on guard duties at certain protected sites which are not accessible to the public,” she said.
British police are chasing down the people they suspect of being behind the bomb, the country’s most senior counter-terrorism officer said.
Mark Rowley said officers were sifting through surveillance footage and examining the remains of the device.