Police arrested three more bombers, accused of the Manchester blast in the city on Wednesday. Abedi’s 23-year-old brother was also among those arrested.
Abedi killed 22 and injured 64, including children, when he blew himself up outside Ariana Grande’s concert on Monday night, which is quoted as the most tragic bomb blast in the UK.
The UK terror threat level has gone up to its highest level of “critical”, meaning more attacks may be imminent and military police are being deployed to protect the important sites.
According to a statement, the Palace of Westminster has been closed for the public following police advice, and will not re-open until further notice.
The Changing the Guard ceremony at Buckingham Palace was also cancelled on Wednesday, to allow for the redeployment of police officers, the Ministry of Defence said.
Home Secretary Amber Rudd said: “[Monday’s attack] was more sophisticated than some of the attacks we’ve seen before, and it seems likely – possible – that he wasn’t doing this on his own.”