Police have maintained a heavy presence on the streets of Liverpool, as counter-terrorism officers investigate a car explosion outside a hospital which killed one person and injured another.
Three men - aged 29, 26, and 21 - have been arrested under the Terrorism Act in connection with the blast involving a taxi at Liverpool Women's Hospital on Remembrance Sunday.
The male passenger of the car was declared dead at the scene and is yet to be formally identified.
The driver, named as David Perry, was injured at the scene and after spending time in hospital, he is now recovering at home.
"Detectives from Counter Terrorism Police North West continue to keep an open mind about the cause of the explosion and are working closely with colleagues at Merseyside Police as the investigation continues at pace," police said in a statement.
Officers were called to the hospital at 10.59am on Sunday.
"So far we understand that the car involved was a taxi which pulled up at the hospital shortly before the explosion occurred," the police statement said.
Images shared online showed a car on fire and later burnt out, with smoke billowing over the building.
Phil Garrigan, chief fire officer of Merseyside Fire and Rescue Service, said the blaze was "fully developed" when his crews arrived and that the injured driver had escaped before it took hold.
He told reporters: "The operational crews extinguished the fire rapidly but as has been reiterated by the police chief constable, there was one fatality.
"Another individual had left the vehicle prior to the fire developing to the extent that it did."
After the explosion, armed police swooped on several terraced houses in Sutcliffe Street, where the three arrests were made.
Sections of Sutcliffe Street and Boaler Street remain cordoned off this morning, with a heavy police presence at the scene as inquiries continue.
A similar police scene is in place at Rutland Avenue in Sefton Park where a number of residents were evacuated overnight from their homes.
A convoy of seven unmarked vehicles - three vans and four cars - entered the cordon in the early hours of the morning.
Counter-terrorism officers are leading the investigation "out of caution" but detectives say they are keeping an "open mind" over the cause.
Liverpool Women's Hospital said visiting was being restricted until further notice, with patients diverted to other hospitals where possible.
"Patients should wait to be contacted for updates about any planned appointments or other attendance at the hospital," it added.
A statement said ambulances were still arriving and that staff could leave and enter "under the supervision of the police".
Liverpool Mayor Joanne Anderson described the incident as "unsettling and upsetting".
"My thoughts are with those affected," she tweeted. "I'd like to thank the emergency services for their swift response and for bringing calm to the situation."
Home Secretary Priti Patel posted to say she was being "regularly updated" on the "awful incident".
"Our police and emergency services are working hard to establish what happened and it is right they are given the time and space to do so," she added.
In a tweet, Prime Minister Boris Johnson said: "My thoughts are with all those affected by the awful incident in Liverpool today.
"I want to thank the emergency services for their quick response and professionalism, and the police for their ongoing work on the investigation."
In a further statement Chief Constable Serena Kennedy said: "While I understand that today's incident may cause concern in our communities, it should be pointed out that events of this nature are very rare.
"There will also be an increased and visible police presence on the streets of Merseyside and I would encourage people to engage with my officers and raise any concerns they may have.
"It is also important that, at this very early stage, people do not speculate about what has happened. We will endeavour to update our communities as soon as we are able."
Speaking to Sky News on Monday morning, Conservative party co-chairman Oliver Dowden said the investigation into the incident continues.
"It is an emerging situation and the home secretary is being kept briefed on it," he said.
"It is a reminder to us all that the threat of terrorism hasn't gone away and how much we depend on our police and security services."