The 50-year-old man who stabbed a Hong Kong policeman on the anniversary of the city's return to Chinese rule on Thursday was a "lone wolf" who committed a terrorist act, Secretary for Security Chris Tang said.

Police said late on Thursday they were investigating an attempted murder and suicide after a man attacked a police officer from behind at 10.05pm, then stabbed himself in the chest with the knife.

The man was sent to the hospital, where he died about an hour later. The policeman, 28, sustained a 10-cm wound on his back and a punctured lung...