Hong Kong police have confirmed an officer fired a warning shot as protesters surrounded them and said they arrested 36 people during the latest pro-democracy demonstration in the semi-autonomous Chinese territory.

A police news release on Monday said that one police officer fell to the ground as protesters threw hard objects at a small group of officers the previous night.

The officers could be seen holding up their shields as protesters surged forward swinging sticks and rods.

The release said that six officers drew their pistols and one of them fired a warning shot skyward.

The incident happened after an earlier clash with hundreds of protesters who occupied a main street following a peaceful protest march.

Police used tear gas to clear the street, but some protesters remained in the neighbourhood.