A furious crowd of about 100 people attacked an urban management office in the capital city of Hainan province, leaving one officer and two security guards injured.

"It was total chaos when those men broke into the office on Tuesday night," Luo Chentan, spokesman for the Haikou Urban Management Brigade, told China Daily yesterday.

"No one was arrested at the scene as the police didn't want the violence to be escalated."

A truck owner whose vehicle had been seized by the urban management officers for allegedly illegally transporting industrial garbage was understood to have organized the protest after claiming the urban management officers had beaten him while impounding his vehicle.

Many of the protesters were believed to be the truck owner's relatives and friends who broke into the office to demand the return of the vehicle and an apology for the truck owner.

As of yesterday, the injured officer and security guards remained hospitalized.

Police have launched an investigation into the case, said Luo.

There have been several incidents recently between the public and urban management officers.

Two urban management officers were stabbed by peddlers in two separate incidents after telling illegal street vendors to move on in Shenzhen, Guangdong province.

One victim subsequently died.

In Tianmen city, Hubei province, last January the manager of a construction company was beaten to death by urban management officers after refusing to delete from his phone footage of a confrontation between the officers and locals.

There has been repeated criticism of the urban management officers for using excessive force. The para-police force is responsible for managing and safeguarding a city's street order.

Luo conceded urban management officers have drawn criticism: "Our task has been a really difficult one because the officers are dealing with a disadvantaged minority that draws sympathy from the public, despite any problems they create putting the public at risk."

To make themselves more appealing to the public, the urban administration officers in Guangzhou changed the colour of their uniforms from dark blue to sky blue on Wednesday. Furthermore, they will not be wearing stab-proof vests like some officers do in other cities when patrolling.

The authority hopes the refreshed look will be more appealing to the public.

Officials are prohibited from accepting bribes, drinking, violently enforcing the law, gambling or privately confiscating articles.