LONDON -- British police responded to a report of an explosion in Leicester, England, that caused a building to collapse along a busy thoroughfare. Six people were hospitalized following the incident, police said, but the cause of the explosion was not immediately clear.

Leicestershire Police said there was "no indication" that the incident was terror related.

Police said they received the report at 7 p.m. local time Sunday and said "a number" of neighboring buildings on Hinckley Road were damaged. BBC News reports that four people injured were listed in critical condition.

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Authorities said "all emergency services" responded to the incident, which closed Carlisle Street and part of Hinckley Road. Businesses and homes in the area were evacuated and taken to a nearby police station as a temporary measure, police said.

Leicestershire Fire and Rescue Service said a two-floor building suffered a "pancake collapse," and said it was unknown if anyone was trapped inside. Officials said there was a hazmat team on the scene.

Video footage from the scene showed rubble on the street and smoke and flames still pouring from a building.

This footage shows the aftermath of an apparent explosion in the Hinckley Road area of Leicester. Police have declared a "major incident." More information as we get it. pic.twitter.com/ghVIGEYjdk — BBC East Midlands (@bbcemt) February 25, 2018

A witness at the scene told CBS News she heard a "bang" and thought it was a car accident. She said emergency services arrived within minutes and that she could see the fire about 200 meters away.

Local fire and police officials will conduct a joint investigation to determine the cause of the explosion.