LANZHOU - Four people were killed and 16 others injured during a fight between two groups of workers after one faction detonated explosives in northwestern Gansu Province on Friday.

The blast occurred at around 2:30 pm near a railway tunnel at a construction site in the Wudu District of the city of Longnan. Workers from the Wuguan highway construction crew, a section of the Lanzhou-Haikou highway, got into a fight with workers from the Lanzhou-Chongqing railway construction team over a parking dispute.

Workers from latter team then detonated explosives to seek revenge, according to a statement from the local government.

The four victims were all from the Wuguan highway construction team. Two of them were killed at the scene, one died on route to the hospital, another died in the hospital, and 16 remain hospitalized.

A further investigation is underway.

The city of Longnan was one of the worst-hit areas in the devastating Wenchuan earthquake in May 2008.

The construction of the Wuguan highway and Lanzhou-Chongqing railway is vital to the reconstruction of the quake-stricken zone.

The sections of the highway and railway are close to each other in the Wudu District, where the explosion occurred, according to the local government.