Four people were killed and five others injured in a clash with railway guards in the port city of Tianjin Monday, the local public security authority said Tuesday.

A large number of unregistered tricycle drivers gathered around the government building of Jinghai County Monday, protesting against the latest government campaign of cracking down upon illegal business of passenger transportation.

The protesters then moved to the Tianjin Jinghai Station of the Beijing-Shanghai Railway in the evening, pushing down fences that cordon off the rail and clashed with railway security staff, according to the public security bureau of Jinghai.

However, some of the protesters were hit or scratched by an arriving train at 8:15 p.m.. Four were killed and the five injured were in a stable condition in a local hospital.

The county began to ban tricycle drivers from illegally transporting passengers in July to protect registered taxi business and restore normal traffic order. Those who defy the official order will face high fines.