BUCHAREST (AFP) - Romania was plunged into mourning on Saturday (Oct 31) after 27 people were killed and 184 injured when a fire ripped through an underground nightclub in Bucharest.

The government declared three days of national mourning and organised an emergency Cabinet meeting, due to start at 10.30am GMT.

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.

The blaze broke out at around 11pm on Friday at the Colectiv night club, where according to witnesses 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.

He said 17 of the 27 dead had yet to be identified.

"Unfortunately, the death toll may change taking into account the severity of their injuries," he said after an emergency meeting early on Saturday.

Of the nearly 200 injured, 146 people were hospitalised for burns, smoke inhalation and other injuries, he said. Hospital sources said nine 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, Mr Arafat said.

President Klaus 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, leaving people scrambling 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, Mr 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," he told online news portal Hotnews.

A young woman who was released from the hospital after minor injuries described the club bursting into flames. "In five seconds the whole ceiling was all on fire. In the next three, we rushed to a single door," she told television station Antena 3.

Several media outlets reported that a second exit happened to be closed at the time when the blaze broke out.

Many of the casualties suffered from leg injuries after being trampled, according to health authorities.

More than 500 firefighters, ambulance crew and police were mobilised.

Police have started an investigation and in the early hours of Saturday groups of sombre-faced officers were still sifting through evidence outside the club.

The authorities set up telephone helplines for members of the public trying to locate friends and relatives, and a Facebook page was set up calling on Romanians to donate blood.

Identifying the victims has proved difficult as many were not carrying IDs. Music website Metalhead has published a list of anyone who has been hospitalised and was able to give their name on its Facebook page.

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.