A witness said a man in his 40s attacked a 24-year-old man and two women aged 26 and 35 with a butcher knife after an altercation with them, the broadcaster RTHK said.
According to the report, the perpetrator later left the crime scene.
WARNING: The following video may offend sensibilities
Vid of knife attack in Lennon Tunnel in Tseung Kwan O circulated on Telegram.— 巴丢草 Badiucao (@badiucao) August 19, 2019
A police investigation of the incident is underway, the broadcaster added.
The injured individuals have been taken to a hospital.