At least four people died and eight others were injured after an expressway bridge partially collapsed due to a truck explosion Friday morning in central China's Henan Province, local government said.

The explosion, which occurred around 8:52 a.m., caused several vehicles to tumble from the bridge in Mianchi County, the city government of Sanmenxia said.

An 80-meter-long section of the bridge collapsed. The exploded truck carried fireworks. Six vehicles have been retrieved from the debris.

Search and rescue efforts are under way. Traffic control was imposed on the expressway.