A Liverpool taxi driver's "heroic efforts" averted what could have been an "awful disaster" on Remembrance Sunday, the city's mayor has said.
His cab pulled up outside Liverpool Women's Hospital and exploded just before 11:00 GMT, as the national two minutes' silence was due to begin.
Joanne Anderson praised the cabbie, named locally as David Perry, for "locking the doors" before the blast.
The taxi passenger died at the scene and Mr Perry was taken to hospital.
Three men have been arrested under the Terrorism Act, while MI5 is assisting regional counter-terrorism police.
Ms Anderson said: "The taxi driver in his heroic efforts has managed to divert what could have been an absolutely awful disaster.
"We knew the taxi driver had stood out, the taxi driver locked the doors.
"Our thanks go to him."
Ms Anderson said Mr Perry was not thought to have suffered life-threatening injuries and was in a "stable" condition and recovering.
The dead passenger has not been formally identified.
Detectives from Counter Terrorism Police North West said three men - aged 29, 26 and 21 - were detained in the Kensington area of the city late on Sunday.
They said they were continuing to keep an "open mind" about the cause of the blast and were working with Merseyside Police as the investigation continued "at pace".