Fire believed to have started when fireworks were let off as part of a show

Chilling pictures have emerged showing the moment fireworks sparked a deadly inferno that killed at least 27 young people at a Bucharest heavy metal concert.

Survivors spoke of the horror that unfolded when fireworks - set off during a pre-Halloween gig in the Romanian capital - sparked a blaze, followed by a stampede as terrified clubbers ran for the exit.

The government declared three days of national mourning amid fears the death toll from the disaster could rise.

The blaze broke out at around 11pm last night 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.

This morning the nation's president Klaus Iohannis said there were 'indications' that safety regulations were ignored at the club.

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Chilling pictures have emerged showing the moment fireworks sparked a deadly inferno that killed at least 27 young people at a Bucharest heavy metal concert

Survivors spoke of the horror that unfolded when fireworks - set off during a pre-Halloween gig in the Romanian capital - sparked a blaze, followed by a stampede as terrified clubbers ran for the exit

Nearly 200 were injured in the fire which reportedly broke out during a song called 'The Day We Die'

A woman lights a candle outside a nightclub, where a fire broke out last night, in Bucharest

Romania was plunged into mourning after 27 people were killed and nearly 200 injured when a fire ripped through an underground nightclub in Bucharest

He said: 'We already have indications that the legal regulations had not been respected. I hope that the authorities manage their inquiry with speed and rigour.'

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.

Nearly 200 were injured in the fire which reportedly broke out during a song called 'The Day We Die'.

Those who were present spoke of the venue being engulfed in flames within seconds. A young girl can be seen smiling and happily chatting to friends as the wall and ceiling behind her burst into flames.

More than 140 were hospitalised for burns, smoke inhalation and other injuries. Hospital sources said nine were in a critical condition.

The band's singer and bassist were said to be in a serious condition, it has emerged.

According to reports, clubgoers initially thought the flames were part of the show and did not immediately react. Fire regulations can be lax in Bucharest clubs and restaurants.

Club-goers told Digi 24 television that a spark on stage ignited some polystyrene decor. Photos posted on social media appeared to show a flame emanating from a pillar covered in foam insulation as those in the audience applauded the band.

A Romanian young woman looks aside as she voluntarily donates blood for the victims of club fire at the National Center of Hematology in Bucharest

A Romanian boy helps her mother to apply a fresh patch after she was voluntarily donating blood for the victims of club fire accident at the National Center of Hematology in Bucharest

A woman is taken into hospital on a stretcher after 27 people died following a blast in a Romanian nightclub

A patient is taken into an ambulance to be transferred to a hospital in Bucharest after surviving the devastating blast

A victim of the fire at the club is transported to an emergency hospital in Bucharest following the incident

After the blast tore through the building, people were seen wandering around outside the club clad in metal blankets in an apparent state of confusion. People were treated for burns and other injuries on the pavement outside the Colectiv Club.

Upon hearing the news, people descended on the club looking for loved-ones.

Adding to their anxiety was the fact that many of the clubgoers were not carrying identity papers so victims could not immediately be identified.

'She's not answering the telephone and she's not saying anything,' said a mother, dressed in a black leather jacket, crying in front of television cameras.

'We want information whether he's alive,' said a visibly overcome woman, speaking about a family member.

Media reported that emergency services arrived 11 minutes after the first call at 10.32pm local time.

Victor Ionescu, who was at the club with his girlfriend, told Antena 3 TV that 'people were fainting, they were fainting from the smoke. It was total chaos, people were trampling on each other.'

A young man filmed by Antena 3 said that flames engulfed clubgoers, burning their skin and hair.

An explosion and a fire at a nightclub in the Romanian capital Bucharest during a Halloween rock concert has killed 26 people. Pictured: A woman comforts her friend as they leave the nightclub

A Romanian woman wraps herself in a thermal first aid foil as she waits outside the nightclub last night

One of the surviving clubgoers stands outside the club as other people are treated around him

Government officials said that at least 88 people were also admitted to hospital after the blast at the Colectiv Club with 154 people injured in total

Several major nightclub fires have been blamed on pyrotechnics igniting foam used for soundproofing.

They include The Station nightclub fire in the US that killed 100 people in West Warwick, Rhode Island, in 2003 and the Kiss nightclub fire in Brazil, which killed 242 people in the university town of Santa Maria in 2013.

Raed Arafat, a government emergency situation official, said people were treated for burns, smoke inhalation and lesions at hospitals around the capital.

'It is a tragedy without precedent and it is an intervention without precedent,' he said.

Mr Oprea called an emergency government meeting for Saturday morning to discuss the situation.

According to the Bucharest-based metal band's Facebook page, lead singer Andrei Gault was the 2008 winner of Megastar, a Romanian show similar to American Idol. The band has five members and has released two albums since it formed in 2011.

President Klaus Iohannis wrote on his Facebook page that he was 'shaken and deeply hurt by the tragic event. ... It is a very sad moment for us all, for our nation and for me personally'.

He said he was considering declaring a day of national mourning.

Prime Minister Victor Ponta, on a visit to Mexico, said he was cutting short his visit to return to Bucharest.

Deputy Prime Minister Gabriel Opera told Romanian TV: 'There are 26 deaths so far'

Emergency services in action outside the club, as they treat dozens of clubgoers who were injured in the blast

A firefighter at the site of the explosion. More than 25 people have now been killed and dozens more are hurt

Government officials said that at least 88 people were also admitted to hospital after the blast at the Colectiv Club

Deputy Interior Minister Raed Arafat said the death toll may still climb at the club, which hosted a rock concert for Halloween attended by up to 400.

He explained that the wounded were admitted to ten hospitals across the city. The health ministry has also launched a public appeal for blood donations.

He added: 'The situation is slowly stabilising ... we have many people with burns, intoxicated with smoke, and people squashed.'

The band Goodbye to Gravity was launching its latest album at the club, called Mantras of War.

Although it has not been confirmed what caused the fire, a local TV station reported that the explosion may have been caused by fireworks.

A witness told local station Realitatea TV one of the fireworks exploded and burned scaffolding that supported the pyrotechnic material.

The scaffolding fell on people who were inside the club and victims claimed the ceiling collapsed.

Victims have reportedly suffered severe burns and others were being resuscitated on the pavement outside of the venue.

A man who escaped without shoes said: 'There was a stampede of people running out of the club.'

Meanwhile the Romanian President Klaus Iohannis said: 'It is a very sad day for all of us, for our nation and for me personally.

People were treated for burns and other injuries on the pavement outside the Colectiv Club in Bucharest

People who escaped from the Colectiv Club in Bucharest are treated by paramedics on the pavement outside

A shot showing the inside of the club in Bucharest, which had been holding a rock concert for Halloween

It is believed that around 400 people were in the club, pictured, at the time for the blast and following fire

'In these moments, expressing my complete sympathy and solidarity with the families of those affected by this tragedy.

'We also assure you the families affected by this event-shattering the full support of all those involved in the rescue and ask them to trust that the agencies, make every effort to ensure the catastrophe is limited.

'I would like you all to stand by the distraught families and to show solidarity and sympathy.'