NAIROBI, Kenya — A runaway tanker carrying volatile gas slammed into other vehicles and burst into flames on a major road in Kenya, killing at least 33 people and injuring 10, officials said early Sunday.

The tanker lost control while going downhill on the road from the capital, Nairobi, to Naivasha late Saturday, said Mwachi Pius Masai, the deputy director and communications officer for the National Disaster Management Unit.

"This is a serious chemical incident," Masai said. "Police and other rescuers are still on the scene ... clearing debris."

Firefighters put out a fire on a burning car which was involved in an accident with an oil tanker in Karai, Naivasha, on December 11, 2016. More than 30 people were killed, authorities said. AFP/Getty Images

He said the death toll could rise. Police said at least 10 people were injured.

Eleven vehicles were burned and continued to smolder. The ground around the crash site was scorched. Residents stood around looking dazed, with some taking photos or selfies with their phones.

"The lorry was in high speed and lost control after hitting speed bumps an ended up ramming into oncoming cars," said witness Peter Kimani.

Kenya has struggled to reduce the rising number of road accidents as more people acquire vehicles in the country's growing middle class.

In 2013, the government re-introduced breathalyzers to limit accidents blamed on drunk drivers.

According to the National Transport and Safety Authority 1,574 died in road accidents in the first half of this year, 86 more deaths than in the same period last year.