LONDON, Feb. 25 (Xinhua) -- There are no early indications that the late Sunday explosion in Leicester City was connected to terrorist activity, reports said.

Carlisle Street and part of Hinckley Road have been closed and police are asking people to avoid the area.

University Hospitals of Leicester NHS Trust tweeted that four patients taken to Leicester Royal Infirmary from the scene of the explosion are in a "critical condition."

Six fire engines were at the scene, Leicestershire Police said. Pictures showed flames rising from a building.

Earlier, local police declare a "major incident" after reports of an explosion in the Hinckley Road area of Leicester.

Leicester Police said on Twitter this evening: "There has been a major incident in the Hinckley Road, Leicester. All emergency services are currently dealing with this."

At around 7:03 p.m., Leicestershire Fire and Rescue received calls from the public who said they had heard a blast in the Hinckley Road.

Dramatic pictures and video shared on social media show flames erupting from a property in the Hinckley Road in Leicester City, which, located in England's East Midlands region, is about 140 kilometers from London.