In Spain, at least three people have died after an explosion that caused a building to partially collapse in the center of the country’s capital, Madrid.

According to city officials, a fourth person was missing and several others were injured. They added that the explosion destroyed four floors of the building and had been caused by a gas leak.

Mayor José Luis Martínez Almeida told reporters that a fire was raging inside the building after the blast.

The incident happened shortly before 3 pm as gas workers were repairing a boiler at the back of the building in the central Puerta de Toledo area of Madrid.

Spanish media reported that a passing 85-year-old woman and two men died while a third person who had been working on the boiler was missing.

Officials have said that one of the injured was in a critical condition and immediately taken to hospital.

The upper floors of the building were destroyed, and these floors were apparently being used to house local priests, Spanish media reported.

Rescue workers evacuated more than 50 people from a care home next-door to the building in Caille de Toledo.

According to the emergency services, nine fire crews and 11 ambulances were at the scene and some of those caught up in the blast were treated on the street.

Police officers cleared the area, closing it to all traffic and passersby, and appealed to local residents not to come near.

“The noise was very loud, very loud, really,” a witness told AFP news agency. “I never heard anything so loud before.”