Photo: The Canadian Press. All rights reserved.

Authorities say a loud explosion has leveled a home in Indianapolis and set four others ablaze in a neighborhood, causing several injuries. Capt. Rita Burris with the Indiana Fire Department told The Associated Press that firefighters are still working to put out the flames after the explosion around 11 p.m. Saturday Nov. 10, 2012. (AP Photo/The Indianapolis Star, Matt Kryger)

A thunderous, late-night explosion destroyed at least two homes in Indianapolis and set surrounding homes ablaze, causing injuries, authorities said Sunday.

The cause of the explosion and fires wasn't immediately clear, but Indianapolis Mayor Greg Ballard dismissed reports of a possible plane crash as he arrived at the scene. Fire officials said separately that investigators would be checking whether natural gas was possibly involved but they had no further details on what was behind the blast that sent tall flames skyward.

Ballard said at least two homes had been destroyed by the powerful blast and that the damage went on "for blocks on end."

Television video showed tall flames shooting overhead and spreading to numerous homes shortly after the blast reported around 11 p.m. Saturday. Hours after the flames pierced the skyline, firefighters had begun containing the flames and thick clouds of grey smoke billowed overhead.

"It was so strong that it clearly had an effect for blocks," Ballard said from the area. Beyond the burning homes there was wider damage in the neighbourhood: windows shattered in nearby homes, walls caved in and garage doors were knocked off their hinges.

Ballard said police have been going door to door, but that it wasn't clear whether there were fatalities. Residents were told to evacuate to a nearby elementary school and people could be seen shivering in white blankets handed out to them as they moved off.

Ballard said investigators will have to see what they find in coming days.