At least 19 people have been killed, including 13 children in a fire at a major shopping mall and entertainment complex in the Qatari capital Doha, according to the country's interior ministry.

The ministry said on Monday that four female teachers and two firefighters were among those killed in the fire, while at least 17 others were injured. Among the children were six boys and seven girls.

Al Jazeera's Stefanie Dekker, reporting from the Villaggio mall, said firefighters were forced to go through the roof of the mall to reach a nursery where the children were trapped.

"The nursery, where most of the children were, is on the first floor with difficult access," our correspondent said.

The health ministry cited suffocation due to smoke inhalation as the cause of death for many of the children and teachers at the Gympanzee nursery.

"We were told the nationalities of the children included Japanese, Filipino, South African, and also European and Arab, but no Qataris," our correspondent said. "Three of the teachers were Filipino and one was African."

She said that the cause of the fire was not confirmed, and authorities were still investigating.

"A witness who was in the mall told me that initially he saw green smoke, and soon after that it turned black and then very heavy," she said.

"He also said that the sprinkler system was not working."

Eyewitnesses reported confusion in the rescue effort, saying they saw no evidence of an organised evacuation plan.

Some among the witnesses reported that the emergency exits in the shopping complex were locked.

Government investigation

Officials said rescue workers were not initially informed that many of those trapped were children. The emergency workers reportedly arrived on the scene within 60 seconds of an initial phone call, but the lack of floor plan delayed the rescue efforts.

Abdullah bin Nasser Khalifa Al Thani, Qatar's minister of state for interior affairs, said a combination of heavy smoke, heat and narrow corridors in the shopping complex forced emergency services to seek an alternative point of entry.

"That entry was from the top of the complex. Time was really critical, and the team took some time because the maps were not immediately available", he said, adding that firefighters had to break through the roof to get to trapped children after a staircase to the first-floor nursery collapsed.

At the evening press conference, the minister expressed his condolence for those that died in the fire, adding that most of the injured were firefighters from the civil defence operation.

Footage posted online showed black smoke billowing from the shopping centre as emergency vehicles rushed to the scene.

The Villaggio is one of the Gulf country's largest and most popular shopping malls, containing a cinema, an ice rink and an amusement park.

The government said that a commission will be formed to investigate the safety standards of buildings in Qatar.