Hong Kong (CNN Business) Hong Kong stocks suffered their worst day in more than three months on Monday as long-running protests in the city saw escalating levels of violence.

Hang Seng Index HSI Thedropped more than 2.6%, its worst single-day percentage decline since the beginning of August, according to Refinitiv data.

Monday's declines came on the heels of new and shocking levels of violence in the Asian financial hub. A traffic officer shot a 21-year-old protester and fired two more live rounds early in the day. The protester had surgery and is in critical condition, hospital authorities say.

Later, in another part of the city, a man who confronted a group of protesters was doused in a flammable liquid and set alight. The incident was captured in a graphic video seen by CNN.

Protests disrupted public transit throughout the city on Monday, as demonstrators blocked roadways and several subway lines experienced delays. Several months of protests have plunged Hong Kong into its first recession in a decade.