"At 5am the death toll was 33 but the search is still on," said Pius Masai of Kenya 's National Disaster Unit. He added that rescuers were continuing to comb the area for bodies. Masai said the accident involved "over 11 vehicles burnt" when the tanker rammed into others on the road and caught fire.
A passenger minibus and a police truck were among the vehicles gutted by the ferocious flames.
The accident occurred at Karai at the bottom of a long downward hill on the busy Nairobi-Nakuru highway, the main cross-country road leading from Kenya 's capital to the west of the country and on to Uganda.
Police and witnesses said the truck with Ugandan registration plates was travelling fast when it hit a speed bump and then lost control ramming into others.
At least 50 people injured in the accident have been received at a private hospital in Naivasha, a foreign news reported.
Witnesses described a fireball engulfing the vehicles with passengers inside. After fire fighters put out the flames rescue workers collected bodies from among the wreckage of charred cars strewn across the highway.