Police have declared a “major incident” after reports of an explosion in the Hinckley Road area of Leicester.
Emergency services said they are conducting a search and rescue operation at the scene.
Carlisle Street and part of Hinckley Road have been closed and police are asking people to avoid the area.
A spokeswoman for Leicestershire Police said all the emergency services were in attendance, including six fire engines.
A Leicestershire Fire and Rescue Service spokeswoman said: “This is a search and rescue at the moment.
“It is unknown if people are injured or trapped.”
The affected property was a two floor building with a loft conversion that had suffered a “pancake collapse”, she added.
Pictures and video shared on social media appeared to show a shop engulfed in flames and the blaze visible from a distance.