RIGA - At least 18 people were killed in Latvia when a supermarket's roof collapsed near the capital Riga, the interior minister said on Friday, more than doubling the previous toll.
Rescuers search for survivors on November 21, 2013 under the rubble at the Maxima supermarket, after a roof collapsed in Riga, killing at least 18 people
"The latest information is that unfortunately 18 people have been killed," Interior Minister Rihards Koslovskis told the LNT TV channel, raising the previous toll of six.
Thirty-five people were injured, some hospitalised in serious condition after the roof came crashing down on Thursday evening.
"We cannot say anything about the cause yet, but it has been a very tragic night," emergency services spokeswoman Viktorija Sembele told AFP.
Three firefighters working at the scene to rescue trapped shoppers were among the dead and 10 rescue workers were injured, she said.
Fire chief Oskars Abolins said: "We are working at maximum capacity but it's a very dangerous situation in the building - it seems likely we will have to continue working all day long."
Television footage showed the roof of the 500-square-metre (600 square yard) supermarket appearing to collapse in two stages, with the second cave-in trapping rescuers already on the scene.
Visiting the scene, Prime Minister Valdis Dombrovskis confirmed that police had launched a criminal investigation to find the cause of the disaster and said he would be holding an emergency meeting Friday morning.
Around 200 rescue workers, backed by military personnel combed through the rubble through the night.
Run by the Lithuanian-owned Maxima chain -- Latvia's number two retailer after Rimi -- the supermarket was built in 2011 and was nominated for an architectural award.
Theories about why the roof collapsed centre on plans to cover it in grass as part of a greening project.
Local council official Juris Radzevics confirmed that plans showed the roof was in the process of being turned into a green area.
"The project was submitted in accordance with all regulations but of course we will be looking at whether materials and works were carried out to the proper standards," Radzevics told the LNT television channel.
Maxima published a statement on its website saying the company was "overwhelmed and shocked" by the disaster but that it was not yet aware of the cause and was providing "all the information at our disposal" to the authorities.