Protesters have attacked police officers during a demonstration in downtown Hong Kong, giving two of them head injuries.

Tensions flared after police ordered protesters to disperse during what demonstrators called the Universal Siege against Communism in the city’s commercial district on Sunday.

Police said in a statement that two police community liaison officers were attacked with wooden sticks and sustained head injuries. They also said some protesters threw water bottles at officers who were conducting a stop and search operation.

In view of the violent incidents, police officers have asked the organizer to halt the public meeting... and urge participants to... leave the area by public transport, the statement said.

An AFP reporter on the scene said a group of plainclothes officers were negotiating with the rally organizers when masked protesters beat them with umbrellas, adding that at least two of the officers were seen with bloody head wounds.

The semi-autonomous Chinese city has been rocked by protests since June over a proposed bill that would have allowed extradition to mainland China. The bill was later withdrawn, but the protests continued, although they have lost much of their steam over the last month.

Still, signs of simmering tensions can be seen around the city, taking such forms as graffiti daubed on walls and huge fences surrounding government buildings.

The protesters say they now demand an independent probe into police brutality and an amnesty for the violent protesters in police custody, among other things.