Hong Kong — Chinese soldiers issued a warning to Hong Kong protesters on Sunday who shone lasers at their barracks in the city, in the first direct interaction with mainland military forces in four months of antigovernment demonstrations.

The stand-off with the People's Liberation Army  came after rallies attended by tens of thousands of protesters earlier on Sunday ended in violent clashes in several locations. Police fired tear gas and baton-charged the crowds, while some demonstrators threw bricks and petrol bombs at police as night fell...