A suspected gas explosion has destroyed a number of buildings and injured 34 people, two seriously.
Footage from the scene on the Wirral, Merseyside, shows alarms blaring as people gather on a street covered in debris, with witness Paul Butler tweeting Sky News and saying: "The whole block has gone up ... horrific damage."
The North West Ambulance service says 32 people are "walking wounded" and received treatment in hospital for minor injuries.
A building being used as a furniture warehouse and a dance studio was destroyed in the blast - and a nearby funeral parlour was also affected.
The explosion, which happened in the New Ferry area, was heard as far away as Liverpool and North Wales.
Ian Kenyon, a reporter for Wirral Radio, said: "A number of people who were eating in a nearby restaurant are reported to have been injured and have been taken to hospitals across the region.
"Thankfully this happened on a quiet shopping street late at night, but residents in the nearby village of Port Sunlight have been evacuated."
He told Sky News a "significant" cordon has been set up around the collapsed buildings, and a smell of gas was reported to the major incident unit and National Grid engineers at the scene.
"There is a certainty toxicity to the air ... floodlights are being erected as they begin the job of sifting through the rubble," Mr Kenyon said.
Merseyrail says trains have been suspended in the New Ferry area because of "potential damage" to a bridge.
The Merseyside Fire and Rescue Service said eight fire engines have been sent to the "major incident" - with extensive road closures throughout the area.
People who have been evacuated from their homes will face a long wait before they are given the all-clear to return.
Spokesman Dan Stephens said: "This incident is likely to be protracted, this is likely to last several days. Very significant damage as you can tell, so it will be some time before people will be allowed back into their houses."
Alison McGovern, the Labour MP for Wirral South, tweeted: "Am on scene in New Ferry. A very serious situation. Please stay away if you can, let police and emergency services do their job."
Emergency crews were called to the scene at 9.14pm on Saturday evening.
Wirral Council says emergency teams have set up a refuge for people who have been displaced by the explosion.
Bino Shan, who works at a local convenience store, said: "I saw one man injured, I think a few people were injured.
"The building is gone, my door is damaged and broken. It's really scary, it was a big explosion but I didn't see any fire."