"Those kids are my kids too," Mahreen Chowdhury told her husband as she lay dying in hospital.

Just hours earlier, the teacher had been standing at the entrance to Milestone School and College in the Bangladesh capital of Dhaka, preparing to hand the second- to fifth-grade students over to their parents.

But in a split second, what had been an unremarkable Monday lunchtime turned to horror.

A Bangladesh Air Force fighter jet crashed into a two-storey building, bursting into flames.

Chowdhury - realising there were students still in the building's classrooms - ran back into the burning wreckage.

"I did my best to pull out about 20 to 25 people - as much as I could," Chowdhury's husband Mansur Helal recalls her saying, moments before she was put on ventilation at the intensive care unit of Dhaka's National Burn Institute. "I don't know what happened after that."

Chowdhury died later on Monday: in the process of rescuing the children, she had suffered burns to almost 100% of her body.

She was among the at least 31 people killed in the accident - 25 of whom are children.

Bangladesh's armed forces said that the F7 jet had experienced a mechanical fault after taking off for a training exercise just after 13:00 local time (07:00 GMT) on Monday, and that the pilot, Flight Lieutenant Md. Taukir Islam, had tried to steer to a less crowded area. He was among those killed.

The crash marks the deadliest aviation disaster the country has seen in decades.

More than 160 people were injured, with an on-duty doctor at the Uttara Adhunik Medical College Hospital saying most were aged between 10 and 15 years old, many suffering from jet fuel burns. More than 50, including children and adults, were taken to hospital with burns, a doctor at the National Institute of Burn and Plastic Surgery said.

Mr Helal told BBC Bangla that he first called his wife after hearing the news of the plane crash. When she didn't answer, he asked his eldest son to go to the school and find out what had happened.

Soon after, he received a call from an ambulance driver telling him that his wife was being taken to the burns unit at Uttara Modern Medical Hospital. She would later be taken to the ICU.

Mr Helal said Chowdhury apologised to him from her hospital bed, shortly before being placed on ventilation. As he recalled their final moments together, he broke down in tears.

"She was still alive. She spoke the highest words with great mental strength. Because almost its hundred percent burn inner and outer," he said.

Chowdhury worked at Milestone School and College for 17 years, having first joined as a teacher before being promoted to become a coordinator in the Bangla department for classes two to five.

She was buried on Tuesday in her home district of Nilphamari, in northern Bangladesh, as flags flew at half mast across the country in a day of mourning for the victims.

Across Dhaka on Tuesday, hundreds of protesting students took to the streets to demand an accurate death toll and the resignation of the education adviser – many of them breaking through the main gate of the federal government secretariat, according to local TV footage.

Police fired tear gas and used sound grenades to disperse the crowd, leaving dozens of people injured, witnesses said.

The protesters called for the crash victims to be named, as well as compensation for victims' families, the decommissioning of what they said were old and dangerous jets, and a change to air force training procedures.

The Bangladesh air disaster comes just weeks after neighbouring India witnessed the world's worst aviation disaster in a decade.

An Air India passenger plane bound for London's Gatwick airport crashed shortly after taking off in Ahmedabad, western India, on 12 June, killing 260 people.

The crash killed 242 people on board the flight and 19 others on the ground, with only one survivor from the plane.