At least two people are confirmed to have died following a suspected explosion at an industrial estate in Norfolk.
Emergency services attended the scene following an "industrial incident" at the estate in Spar Road, Hellesdon, in Norwich.
Norfolk Police said two men, one in his 50s and another in his 20s, have died following the incident.
Initial reports suggested there were many injured in the suspected blast, however a police spokesperson said "no-one else required medical attention".
Firefighters from Norfolk Fire and Rescue Service and the Air Ambulance Service also attended the scene.
Keith Swann, 56, branch manager of nearby Automotive Parts Distribution, told the Eastern Daily Press: "There was a big cloud of black smoke behind us. We could see the black smoke coming across the top of the building and it went really dark. We didn't know what was going on. Ten minutes after that, the air ambulance arrived."
A Norfolk Police spokesperson said: "Officers can confirm that two people have sadly died at the scene of an industrial incident that happened earlier this morning [Monday 13 July] in Hellesdon.
"Initial reports from the scene suggested an explosion had taken place. The men, one aged in his 50s and one in his 20s, both thought to work at the premises involved, died as a result of the incident shortly after 9am. No-one else required medical attention.
"Road blocks remain in place at Spar Road to the junction with Vulcan Road North and Vulcan Road South and the bottom of Concorde Road."
A spokesperson for The East of England Ambulance Service Trust added: "We received a call at 9.10 this morning to reports of an explosion in Norwich.
"We sent two ambulances, the first of which was on scene in 6 minutes, an ambulance officer, the east Anglian air ambulance and the Hazardous Area Response Team.
"Our crews worked alongside fire and police colleagues and treated a number of patients. We treated three patients with smoke inhalation and they were discharged from scene.
"Unfortunately two people sadly died at the scene."