There are "indications" safety regulations were ignored at a Bucharest nightclub where a fire and stampede killed 27 people, Romanian President Klaus Iohannis says.
"We already have indications that the legal regulations had not been respected," Iohannis said.
"I hope that the authorities manage their inquiry with speed and rigour."
Romania has plunged into mourning after a fire ripped through an underground nightclub in the country's capital.
Survivors spoke of the horror that unfolded when fireworks - set off during a pre-Halloween gig by a heavy metal band - unleashed a blaze, followed by a stampede as terrified clubbers sought the exit.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The government declared three days of national mourning and was holding an emergency cabinet meeting on Saturday morning.
The blaze broke out just before midnight on Friday at the Colectiv nightclub, where between 200 and 400 youngsters had gathered for a performance by rock group Goodbye to Gravity.
Twenty-six people died in the club and one died in hospital, the secretary of state for the interior, Raed Arafat, said after a meeting of a national emergency committee.
Of the nearly 200 injured, 146 people were treated at hospitals for burns, smoke inhalation and other injuries.
Hospital sources said 10 were in a critical condition.
The band's singer and bassist were said to be in a serious condition, according to local reports.
"This is the worst tragedy of its kind" to have ever happened in Bucharest, Arafat said.
Iohannis said he was "shocked" and in "deep pain".
"It is a very sad moment for our nation," he said in a post on his Facebook page, expressing his "solidarity and compassion" for the families of the victims.
Witnesses described nightmarish scenes when fireworks, let off as part of a show to promote the band's new album, set fire to a pillar and part of the ceiling.
The crowd panicked as thick smoke engulfed the room, prompting people to scramble to escape from the club, located in a communist-era basement.
"People were fainting, they were fainting because of the smoke. It was total chaos, people were trampled," witness Victor Ionescu told local television station Antena 3.
Another witness, Alin Panduru, said the fire spread "in 30 seconds".
"People could not get out of the club because there was only one exit open and the stampede happened immediately," Panduru told online news portal Hotnews.
Several media outlets reported a second exit was closed at the time the blaze broke out.
Identifying the victims has proved difficult as many were not carrying identification.
Fireworks and restricted exits have been a lethal combination in many nightclub fires around the world.
In one of the worst such disasters, 156 clubbers in the Russian city of Perm died in 2009 in a blaze caused by pyrotechnics, and 83 were injured.
Seven people were jailed for up to nine years after the tragedy.
AFP ab/rwj
