A male passenger in the car was declared dead at the scene, while the male driver was injured and was in hospital in a stable condition, police said.

Counter-terrorism officers said they were investigating the case with local police and that they were keeping an open mind as to what had happened.

British Prime Minister Boris Johnson said his thoughts were with those people affected and interior minister Priti Patel said she was being kept regularly updated.

Three men - aged 29, 26, and 21 - were detained in the Kensington area of the city and arrested under the Terrorism Act, police said in a statement.

Police officers keep guard outside a house in the Kensington area where counter-terrorism officers arrested men after a vehicle exploded outside Liverpool Women's Hospital in Liverpool, Britain, November 15, 2021. REUTERS/Phil Noble Police officers keep guard following a car blast outside Liverpool Women's Hospital, in Liverpool, Britain, November 15, 2021. REUTERS/Phil Noble A forensic police officer walks outside an address in the Sefton Park area, following a car blast outside Liverpool Women's Hospital, in Liverpool, Britain, November 15, 2021. REUTERS/Phil Noble

1/3 Police officers keep guard following a car blast outside Liverpool Women's Hospital, in Liverpool, Britain, November 15, 2021. REUTERS/Phil Noble

Chief Constable Serena Kennedy said police were called to reports of a car explosion just before 1100 GMT outside Liverpool Women's Hospital, just as a Remembrance Day Service was commemorating war dead at the nearby Liverpool Cathedral.

Police said they understood that the car involved was a taxi that pulled up at the hospital shortly before the explosion occurred.

"Work is still ongoing to establish what has happened," Kennedy told reporters.

"We are keeping an open mind as to what caused the explosion but given how it has happened, out of caution, counter-terrorism police are leading the investigation supported by Merseyside Police."

Police said the explosion had not been decla