A police officer fired two shots as he chased three suspects outside Shek O village at about 9.30pm last night.
The officer fired the shots after the suspects, who were described as Chinese in appearance, threw stones at him and hurt him on the left leg, according to Sammual Lam Siu-wah, chief inspector of Eastern District's crime squad.
The suspects escaped into the hills and the search for them was continuing after midnight last night, with officers blocking paths in the area.
Lam said officers had been sent to Shek O after police received a report at around 3pm saying suspicious people had been spotted near the village.
Three plainclothes officers encountered the male suspects at around 9pm, half an hour's walk from a beachside barbecue site, said Lam.
After the officers identified themselves, two of the three suspects then began to pick up stones and throw them at the police.
One of the three officers pulled out his gun and warned the suspects to stop. He then fired one shot after his warning was ignored, according to Lam.
However, the two men continued to throw stones at the officers and ran towards the officer who had fired. He then fired again after another warning to stop was ignored.
"The two shots are justified," said Lam. "There was little light in the hills and our colleagues felt their lives were threatened.
"The suspects threw stones at them and [the officer who fired the shots] did get hurt. He only fired the shots after his warning were ignored."
After the second shot, Lam said, the suspects ran away.
The Flying Service initially joined the search for the suspects but turned back near North Point due to weather issues, he said.
Officers said there had been a recent burglary in the village.
The injured officer was taken to Pamela Youde Nethersole Eastern Hospital.