Authorities in the southwestern Chinese city of Chengdu said on Saturday that the DNA of the 25 people killed in a bus blaze on Friday has been collected to help confirm their identities.

Mao Zhixiong, a government spokesman, said 20 of the 76 injured passengers on the bus are still in serious condition, most suffering burn injuries.

Three slightly injured people have been discharged from hospital.

Among the injured, 35 are male and 38 are female. The oldest one is 72 years old, and the youngest is five.

The 20 serious injured are under intensive care in four hospitals, which boast the best medical conditions in the city, said Mao.

An investigation, led by Sichuan Vice Governor Li Chenyun and including officials from the Sichuan government, the Public Security Ministry and the State Work Safety Administration, started on Friday.

The fire began at morning rush hour Friday, when the No.9 bus, with license plate Chuan A 49567, was on its way from Tianhui Township to downtown Chengdu, and caught fire under the Chuanshan Viaduct, said Mao.

"The bus had air conditioning and only the windows at the rearmost seats could be opened by hand," said 29-year-old Deng Huaqiong. She sat on the second row from the rear and jumped out after someone opened the back window. She suffered slight burns and was receiving treatment in hospital.

Passers-by smashed the windows from the outside, which helped save some of passengers.

The bus was diesel-powered and made in February 2005. It had 270,000 km on the odometer.

(Xinhua News Agency June 6, 2009)