People were still trapped inside the Gulistan building where at least 15 people have died, hours after a fiery explosion ripped through the 5-storey block on Tuesday evening.

People on the upper floors became trapped inside as it was not possible to get to the ground floor, as the columns holding up the building from the ground collapsed, said Brig General Md Main Uddin, director general of Fire Service and Civil Defence.

“We are unable to enter the ground floor because the building is now at risk due to the collapse of the columns. So, we are taking the help of the army,” he made the remarks while replying to a question from reporters after visiting the site of the blast in Fulbaria area of Gulistan.

Since the Fire Service chief spoke, the chairman of RAJUK has however been able to confirm that everyone inside has, to the best of everyone's knowledge, been evacuated.

“The explosion took place at 4:50 pm. On receiving the news, our team reached the spot within seven minutes. As the building is risky, we cannot enter now. But we will take it to a slightly stable level and then start the rescue operation on the ground floor. Work is currently underway,” he said.

“The army's help will be taken in the rescue operation, that's why the excavator came. So far, the death toll is 15 and the number of injured is 40. If we have more information, we will let you know later,” the DG added.

The fire chief also deliberated on possible causes behind the disaster, although he was careful to add that at the time, nothing was known for certain.

"We spoke to the members of the owners' association here a while back and they said there was no gas line below but there was a water line. There was a water reservoir. We still don't understand what the reason for the explosion is. The army's expert team has arrived. They will now work to see if there is any other reason. We'll let you know - it'll take a while,” he said.

When asked if they found evidence of any explosives, Brig General Md Main Uddin: "We have not received anything like this so far. As of now, I can't say why this happened. An army expert team has come and they will look into the matter and an expert team of the police has come. We hope to come to a conclusion together with the police and the army.”

Brig General Md Main Uddin did dangle out one clue as he wrapped up his presser, saying there were eight shops on the ground floor of the building: "All of which sold sanitary products."