An initial investigation into the Kenya boarding school fire which killed 17 students this week has revealed the school dormitory where students were sleeping was "overcrowded, in violation of safety standards", Kenya's National Gender and Equality Commission said.

The government has urged school administrators to enforce boarding guidelines that require dormitories to be spacious, with three doors and no grills on the windows for easy escape in case of fires.

The flames engulfed a dormitory at Hillside Endarasha Academy in the central Nyeri county at around midnight, local time, on Thursday. 

Government spokesperson Isaac Mwaura said the students were in grades 4 to 8, putting their ages at about 9 to 13 years old. He said in a statement the dormitory housed 156 students.

President William Ruto said on Friday that 17 students had lost their lives, while 14 had sustained injuries and were being treated in hospital.

"I pledge that the difficult questions that have been asked such as how this tragedy occurred and why the response was not timely will be answered; fully, frankly, and without fear or favour," Mr Ruto said in a statement.

"All relevant persons and bodies will be held to account."

DNA testing underway as 70 students still missing

Vice President Rigathi Gachagua said on Friday that 70 students were still unaccounted for following the fire.

Many family members broke down after officials took them to see the bodies in the destroyed dorm on Friday.

"Please look for my kid. He can't be dead. I want my child," one woman said.

Interior Minister Kithure Kindiki said while visiting the school that many students jumped from the burning dormitory to safety, but "we do not know how many were successful"

He later wrote on X that the government would ensure "full accountability" would be taken against those "whose action or inaction contributed to this tremendous loss".

He appealed for local residents who took in survivors to bring them back to the school so that they might receive medical help and counselling.

Kenya police also stepped up their investigations Saturday, with homicide investigators and forensic experts at the site.

The charred bodies of victims, which police had said were burnt beyond recognition, were still in the dormitory.

"Today we want to begin the process of DNA testing," Kenya's chief homicide detective Martin Nyuguto said.

Three days of national mourning to start Monday

Mr Ruto declared three days of national mourning starting from Monday after what he described as an "unfathomable tragedy".

In a statement from the Vatican on Saturday, Pope Francis said he was "deeply saddened" at the loss of young life and expressed his "spiritual closeness to all who are suffering the effects of this calamity, especially the injured and the families who grieve".

The Kenya Red Cross said it was on the ground assisting a multi-agency response team and providing psychosocial support to traumatised pupils and families.

Muchai Kihara, 56, said he was lucky to find his 12-year-old son Stephen Gachingi alive after rushing to the school at around 1am, local time, on Friday.

"I cannot begin to imagine what he went through. I am happy he is alive but he had some injuries at the back of his head and the smoke had affected his eyes," he said.

"I just want him to be counselled now to see if his life will return to normal."

School fires are common in Kenyan boarding schools, often caused by arson fuelled by drug abuse and overcrowding, according to a recent education ministry report.

Kenya's deadliest school fire in recent history was in 2001, when 67 students died in a dormitory fire in Machakos county.

AFP/AP/Reuters