HONG KONG — Violence returned to the streets of Hong Kong on Saturday, as the police fired tear gas and protesters threw stones and gasoline bombs, signaling the end of a period of relative calm in the city.

The clashes in the district of Kwun Tong, in eastern Kowloon, were a marked departure from the peaceful, if sometimes tense, gatherings that had taken place over much of the last two weeks.

Just a day earlier, antigovernment demonstrators had held hands across Hong Kong, forming human chains to demand greater democracy in the semiautonomous Chinese territory.