A tourist bus fell into a 10-meter-deep valley from a highway bridge in Southwest China's Guizhou province at about 6:40 pm on Wednesday. As of 10:30 am on Thursday, 18 people were killed and 40 injured.  [Photo/Xinhua]

GUIYANG - Two more have died raising the death toll to 18 after a bus plunged off bridge in southwest Guizhou Province Wednesday, local authorities said Thursday.

The 53-seat bus with 57 passengers aboard, including four infants, fell off the bridge and into a 10-meter-deep crevice at about 6:30 pm while traveling on an icy section of the Lanzhou-Haikou expressway in Guiding county, said a spokesman with the county government.

An initial investigation found that the driver was fatigued and speeding, according to the spokesman.

Among the 37 injured, six are in critical condition.

The bus was heading to Xuyong county, Sichuan Province from Yiwu city, Zhejiang Province, and registered under the Kaihong Passenger Travel Co. in the city of Huangshan, Anhui province.

A further investigation is under way.

The accidents occurred as the annual Chinese New Year travel rush is about to start. About 2.85 billion people are expected to hit the roads during the travel peak from Jan 8 to Feb 16.

The Chinese New Year, the most important family reunion occasion for Chinese, falls on Jan 23 this year.