The terror threat level in the UK was raised following a bombing at the Manchester Arena on May 22 that killed 22 people and injured more than 120 others.
The bomber, identified by police as 22-year-old Salman Abedi, also died in the explosion. Abedi was born in Manchester to parents who had emigrated from Libya.
The Joint Terrorism Analysis Centre raised the threat level to “Critical”, its highest level, which means JTAC believes a terrorist attack is imminent.
The government is deploying 984 soldiers to support police, under the Operation Temperer plan. UK police are not normally armed, and firearms-trained officers are being freed up for other purposes.
Metropolitan Police Assistant Commissioner Mark Rowley said 1,000 additional officers have been deployed across the UK.
Reacting to the deployment of troops, Steve White, chair of the Police Federation of England and Wales which represents rank and file officers, said that the use of the armed forces was a significant change.
“There is no ignoring the fact that we, the police, simply do not have the resources to manage an event like this on our own,” he said.
Around 20,000 police jobs have been axed since 2010 and budgets were cut by around 4% per year when current Prime Minister Theresa May was Home Secretary.
Police investigating a network
Greater Manchester Police Chief Constable Ian Hopkins said on Wednesday that investigators believe Abedi did not act alone.
“This is clearly a network that we are investigating, and extensive activity is taking place across Greater Manchester as we speak.
There are no military personnel patrolling Manchester but we are therefore able to receive additional armed policing support because of this [the Operation Temperer] plan.”
Greater Manchester Police chief constable Ian Hopkins
The Manchester Evening News reported that police believe the person who made the bomb is still at large.
Police have said they are confident they know the identity of all the victims, but forensic post-mortems are likely to take several days.
Seven arrests in the UK, two in Libya
Early on Wednesday, Greater Manchester Police carried out raids of at least two properties, one on Granby Row in the city centre and one in Aston Street in Fallowfield, near where the bomber lived. Three men were arrested.
On Wednesday night, a man was arrested in Nuneaton in Warwickshire in connection to the bombing.
Abedi’s brother Ismail was arrested in Manchester on Tuesday.
Reuters reported Abedi’s younger brother Hashem was arrested in Tripoli, Libya on Wednesday on suspicion of Islamic State links, and Bloomberg reported that Ramadan, the suspected bomber’s father was also arrested in Libya.
Home Secretary Amber Rudd criticised leaks of UK information by US intelligence services. She said authorities want to control information flow and described US leaks as irritating. Rudd said she told US officials that it must not happen again.
Several hours after Rudd’s criticism, NBC News reported that an unnamed US official said the bomber likely “had help” making a “big and sophisticated bomb,” that he was identified by a bank card in his pocket, and that his family warned about him in the past, saying he was dangerous.
NBC also said Abedi had ties to al-Qaeda and had received terrorist training abroad.
Later, the New York Times published detailed images of what it said was the bomb.
Reacting to the leaks, a spokesperson for the National Police Chiefs’ Council said that, while it valued important relationships with trusted intelligence, law enforcement and security partners around the world, breaching that trust “undermines these relationships, and undermines our investigations and the confidence of victims, witnesses and their families.”
“This damage is even greater when it involves unauthorised disclosure of potential evidence in the middle of a major counter terrorism investigation,” the spokesperson added.
Mayor of Greater Manchester Andy Burnham said he spoke to the US ambassador about US officials leaking details of the investigation.
Prime Minister Theresa May will speak to Donald Trumpabout the leaks at a NATO summit in Brussels on Thursday, The Guardian reported.