Officer pinned between cars during attempted arrest

But as he approached the car, the driver accelerated, pinning the sergeant between two cars.

The officer fired his gun, hitting the car before it drove off.

He was taken to hospital with lower leg injuries in a stable condition.

About half an hour later, a 32-year-old man suffering a gunshot wound was seen limping along a street in Ryde. 

Police found him and the abandoned car in the yard of a home on the other side of the block.

He was taken to hospital in a stable condition, where he remains under police guard.

The same night, in an unrelated incident also in Sydney's south-west, another police officer was injured on duty after a public shooting in Chester Hill.

Several shots were fired from a black ute into another car at about 11.30pm.

Both vehicles left the scene before police arrived but a 26-year-old man arrived at Auburn Hospital about five minutes later with gunshot wounds.

Police found a Mercedes in the hospital car park with a number of bullet holes.

When police attempted to speak to a 30-year-old man in the emergency room, he repeatedly punched the 58-year-old chief inspector in the head.

The 30-year-old was charged with assaulting a police officer in the execution of duty and refused bail.

The officer was treated for a laceration to the head.

The 26-year-old remains in a critical condition.

In a third separate incident earlier in the day, a police officer was taken to hospital earlier after a foot pursuit in Bankstown.

While patrolling a hotel on Wednesday morning, police were speaking to a 33-year-old man when he ran, triggering a chase.

The man and an officer ran onto the road when they were struck by an SUV.

Both were treated at the scene and the 33-year-old was taken to Liverpool Hospital in a stable condition.

Police later found drugs on the man and arrested him.

The officer involved in the chase was taken to hospital to be checked for leg and head injuries. 

The SUV driver was not injured.