HONG KONG — A Hong Kong police officer shot an antigovernment demonstrator on Monday, an escalation that quickly inflamed tensions in the city already jittery over the recent death of a student involved in the protests.

The officer fired several shots on Monday morning toward two black-clad protesters in a neighborhood where traffic had been snarled by roadblocks. One of the protesters crumpled to the ground after being hit at point-blank range, video footage from the scene shows, and appeared conscious afterward.

The shooting on Monday came as pro-democracy activists in Hong Kong blocked roads and scuffled with riot police officers across the city as part of what had been billed as a citywide general strike.

It has been 23 weeks since protests began in the semiautonomous Chinese city over a contentious, but since-withdrawn, extradition bill. The demonstrations have since morphed into calls for greater democracy and police accountability.