The Bucharest nightclub fire that erupted on Friday was the result of neglected safety regulations, Romania’s president said after the incident.
According to Romanian authorities the fire killed 27 people and injured 155 more.
Over 400 people were considered to have been present at the concert given by the rock band Goodbye to Gravity.
During the concert, the rock band set off fireworks which resulted in the ceiling and a pillar catching on fire.
Although there were to two small exit doors, one of them would not open and had to be broken down to exit out of.
Nearly 150 people were injured and taken to the hospital for necessary treatment, 35 are known to be in critical condition.
"I am saddened, but also revolted that a tragedy of this scale could have taken place in Bucharest," President Klaus Iohannis said as the country declared a three-day national mourning for the lives lost.
"We already have indications that the legal regulations had not been respected," he said.
"I hope that the authorities manage their inquiry with speed and rigour," he concluded.
"People were fainting, they were fainting because of the smoke. It was total chaos, people were trampled," witness Victor Ionescu told local media.
Meanwhile, autopsies of the victims begun on Sunday while authorities are at the accident scene assessing the situation.