Police in Sweden are hunting a suspect in connection with an explosion and fire at a block of apartments that injured 16 people, four of them seriously.
The man is said to be 55 years old and had been living with his mother in the building in Gothenburg, according to local reports.
Officers have not disclosed the name of the man, who is wanted on suspicion of public destruction.
One neighbour told Sverigesradio there had been concerns about chemical smells coming from the basement.
“We still do not know what caused the explosion,” senior police officer Anders Borjesson said on Thursday.
“The investigation is far from over. We still have a lot ahead of us.”
Reports in the Swedish media initially suggested the incident could have been linked to feuding gangs in the area but police have since said they do not believe gang activity played a part.
Mr Borjesson declined to give details on the suspect, saying only that the warmth and lack of oxygen in the building had made it difficult for investigators to do their work.
Hans-Jorgen Ostler, spokesman for the regional police, urged the public not to approach a man if they believe he is the suspect.
“It is clear that if you see the person, you should not try to arrest him yourself but call the police,” he said in comments carried by Swedish newspaper Aftonbladet.
The appeal comes after a blast at a building in Gothenburg shortly before 5am on Tuesday morning, sparking a fire that spread to several apartments. One victim is in intensive care.
Panicked residents were sent fleeing to their balconies, with some using sheets tied together to lower themselves to the ground.
At least one person fell from a balcony, according to witness Lars Hulten, who lives in the building.
"The whole apartment vibrated, the bed vibrated," Mr Hulten told the Göteborg Tidning newspaper. He also described how his neighbours "hung from balconies” and said “there was one who fell" after the explosion.
Jon Pile, operations manager at the greater Gothenburg rescue service, said the flames spread to several apartments.
“It was burning in several places in the property and in several apartments after the explosion,” he said.
He told a news conference that the explosion appeared to have occurred in the building’s inner courtyard, which had its entry gate blown off.
Sweden’s home affairs minister Mikael Damberg told Swedish news agency TT that it was awful to see the devastation caused by the blast.
“Many of us now want answers to what happened and the cause of this terrible event,” he said.
Police have yet to determine the exact cause of the blast but believe it was “not of natural causes”.
Police spokesman Thomas Fuxborg said something had probably been placed at the site of the explosion.