Thirty-three people died on Saturday night when a truck carrying inflammable substances rammed into several vehicles before bursting into flames near Karai on the Nairobi-Naivasha Highway, the government has confirmed.
Earlier, deputy county commissioner Isaac Masinde had said at least 40 had died.
Two survivors of the accident have been admitted at the Nairobi hospital; one in the Intensive Care Unit (ICU) and while the other is said to be in stable condition.
Witnesses at the scene said the driver of the tanker lost control and hit the other vehicle which created chain of knocks.
The accident on the busy highway, some 80 kilometres west of Nairobi created a horrible scene.
Four victims of the Saturday night accident were taken to the Naivasha Mt Longonot Medical Centre while two were treated and discharged. Two others, according to the Clinical Officer at the facility Dalmas Otumba, were taken to Nairobi hospital for specialised treatment.
According to a preliminary police report released on Sunday morning, the truck (registration number UAK 519C) hit a bump before its driver lost control and rammed into a vehicle in front and other vehicles before it burst into flames.
"The fire spread very fast burning 10 other vehicles. A General Service Unit (GSU) Land Cruiser registration number GK B 961G was also burnt, killing the officers on board. Most bodies were burnt beyond recognition," said the police report.
"At the scene, two containers of premium bond substance said to be highly flammable were recovered and suspected were among the items carried in the truck," added the report.
Nation reporters at the scene, on Sunday morning, counted 12 shells of burnt out vehicles and confirmed there are two bumps at the section of the road where the accident happened.
Transport PS Irungu Nyakera, while addressing the media on Sunday morning at the scene, said that nine police guns were also recovered and put the death toll at 33.
National Disaster Management Unit boss Pius Maasai has advised those who lost their loved ones to report at Naivasha Police station for assistance.
According to him, most of the bodies can be identified.
All the bodies, Mr Maasai said, will be taken to Naivasha mortuary.
The Kenya Red Cross has set up an information desk at the Naivasha police station where relatives have been urged to report their missing ones for identification.
NTSA boss Francis Meja confirmed that 12 vehicles were burnt, adding that one was a PSV and the rest private.
The matatu was carrying 14 passengers, who all perished.
The tanker, which was coming from Nairobi, was negotiating the hilly part of the road, before knocking a matatu and exploded into flames.
Earlier, a Kenya Red Cross official said rescuers had taken 30 bodies to Naivasha Sub-County Hospital Mortuary.
The accident happened on the fifth day of a national strike by doctors and nurses.
Karai is about five kilometres from Naivasha Sub-County Hospital, one of the facilities affected by the industrial action.
Doctors have claimed the government must fulfill the conditions in the Collective Bargaining Agreement signed in 2013; to increase their pay, improve working conditions and hire more doctors to reduce workload.
On Saturday evening, nurses announced they had agreed on a return to work formula.
But the final decision to call off the strike rests with the outcome of a planned meeting of the National Executive Council of the Kenya National Union of Nurses on Sunday.
Among the burnt vehicles was a pick-up truck carrying administration police officers that was heading to Nairobi.
Three of them are among the dead. Eight magazines of the guns they were carrying were recovered.
Mr Edwin Wafula, a survivor who suffered burns on his hand, told the Nation he was travelling to Nairobi in the company of four other people when their car caught fire.
“The fire caught cars on both sides of the road. The truck was coming from Nairobi, but those heading to the city were also burnt,” he said at the scene.
Rescue workers from the Kenya Red Cross arrived at the scene moments later but they are having a hard time because there is a snarl-up.
Mr Peter Njoroge said he had been trailing the truck in his car when it suddenly veered off its course to the lanes of oncoming vehicles. It exploded shortly afterwards.
“I was a distance away and that enabled me to slow down and reverse,” he told the Nation.
“It was a huge explosion and other motorists had little chance to react.”
The highway, the main artery that links the city to western Kenya, and on to neighbouring countries of Uganda, Rwanda, Democratic Republic of Congo and South Sudan.
It is considered by the World Health Organization among the most dangerous roads to drive on. At least an accident happens every three days.
Additional reporting by Eric Matara, Fred Mukinda, Aggrey Mutambo, Magdalene Wanja, Stella Cherono and Angira Zadock.