An explosion ripped through a four-story residential building in central Madrid on Friday, injuring at least 18 people.
Emergency services in the Spanish capital said they were searching for two missing people.
Video released by the city of Madrid showed paramedics attending to the injured at the scene in the upmarket neighborhood of Salamanca, as police and firefighters cordoned off streets cluttered with glass and debris.
Four of the injured were taken to a hospital, including one person in serious condition, after the blast sent plumes of smoke billowing over parts of the area.
Emergency crews combed the building to check the structure and to search for anyone trapped inside, Madrid Mayor Jose Luis Martinez-Almeida told broadcaster Telemadrid.
Asked about reports saying a gas leak had caused the explosion, the mayor said it was too early to know.
“What is known is that some work was being done in the building, and neighbors said there was a powerful explosion,” he said.
Spanish Prime Minister Pedro Sanchez said in a tweet that his office was closely following the situation. “I’ve just called Mayor Almeida in order to convey my solidarity and support to the victims of an explosion in a building in Madrid,” he said.