SYDNEY, June 6 (Xinhua) -- Three people, including a teenager, have been killed in separate crashes within hours on roads in the Australian state of New South Wales (NSW).

Police in NSW said that a 16-year-old boy was killed and three more people were injured when a truck and a hatchback collided in the southwest Sydney suburb of Greenacre shortly after 8 p.m. on Thursday.

Emergency services were called to the scene where the 16-year-old, who was a passenger in the hatchback, was declared deceased.

A second passenger, another boy, and the female driver of the hatchback were treated by ambulance paramedics before being taken to the hospital in critical condition.

The third passenger in the hatchback, an adult male, was hospitalized in stable condition, and the driver of the truck was taken to the hospital for mandatory testing.

Earlier on Thursday night, a female pedestrian aged in her 40s died after being struck by a vehicle in Penrith, 50 kilometers west of central Sydney.

A police statement said that the driver fled the scene without stopping.

In a third fatal incident, a 20-year-old man died after his vehicle crashed into a tree near the southern NSW town of Henty about 10 p.m. on Thursday.

Police established crime scenes at the locations of all three incidents and commenced investigations into the causes of the crashes.

NSW Police also said on Thursday night that an 85-year-old man who was struck by a vehicle while walking in northern Sydney on Tuesday has died in hospital. ■