At least three people have died and four remain missing after an underground fire, followed by a blast, at a hydroelectric power plant in northern Italy on Tuesday. Another five people were hospitalized with serious injuries, according to Ansa news agency.

Initial reports said that a fire broke out on the eighth floor underground, some 30 meters deep, in one of the two units of the plant. An explosion followed shortly after.

The Italian utility group Enel confirmed that a fire had struck one of its transformers at its hydro power plant in Bargi, close to Bologna in early afternoon. All those involved were working at the plant when the explosion took place.

(With input from agencies)