An explosion tore through a four-story residential building in Trévoux in the Ain department of eastern France, heavily damaging the ground floor and killing two children aged three and five.Authorities deployed 50 firefighters, 36 vehicles, 45 gendarmes and medical teams, activated the NOVI plan, mounted canine searches for a missing occupant and said 13 people were injured while Laurent Nuñez said he will visit the site the following morning and offered condolences.