The mayor of the northeastern U.S. city of Middletown, Connecticut, says at least five people have been killed and 12 others injured by an explosion at a newly constructed electrical power plant.
Mayor Sebastian Giuliano said the Sunday morning blast damaged the main generating building of the Keene Energy facility, and resulted in a large fire.
After the fire was extinguished, search teams began looking for victims amid the wreckage of the plant. Officials say casualty figures may rise as the searchers work through the night.
Fire officials say they have not yet determined how many people were inside the building when it exploded. The power plant was in the final stages of construction, and there were a number of different contracting companies working at the site.
Authorities say natural gas, which powers the plant, was the source of the blast.