HONG KONG >> Anti-government protesters attacked the Hong Kong office of China’s official news agency in a show of anger against Beijing after chaos broke out downtown on Saturday, with police firing tear gas to repel gasoline bombs.

Streets in the upscale Causeway Bay shopping area and nearby Victoria Park were clouded in tear gas, sending thousands of protesters fleeing as riot police moved swiftly to stymie the latest rally in the city’s 5-month-long push for genuine autonomy.

Police deployed at least two water cannon trucks in the vicinity. They had issued warnings to protesters who occupied the area that they were taking part in an unauthorized rally and were violating a government ban on face masks.

Some protesters stormed Xinhua News Agency’s office in the city’s Wan Chai neighborhood, smashing windows and the glass entrance door, splashing red ink, spraying graffiti and setting a small fire in the lobby. Graffiti that was sprayed on the wall next to the entrance read “Deport the Chinese communists.”

It was the first strike against the Chinese state-run news agency, a day after the ruling Communist Party in Beijing vowed to tighten the grip on the territory.

Protesters have frequently targeted Chinese banks and businesses linked to or that support China. In July, demonstrators threw eggs at China’s liaison office in Hong Kong and defaced the Chinese national emblem in a move slammed by Beijing as a direct challenge to its authority.

Protesters accuse China’s central government of infringing on the freedoms guaranteed to Hong Kong when the former British colony returned to Chinese control in 1997.

Earlier Saturday, some protesters unearthed a goal post from a soccer field and metal railings to block the entrance to Victoria Park.

Pro-democracy candidates running in this month’s district council elections — who can meet with groups of 50 or fewer people without a police permit — held meetings with voters at the park to try get around the rally ban. One candidate was pepper-sprayed in the face and detained after he argued with police.

Pockets of hardcore protesters in full gear quickly regrouped, setting street barriers and thrashing shuttered subway station exits. Protests also spread to the Kowloon district late Saturday.

In multiple places around the city, protesters hurled gasoline bombs at police, who responded by firing tear gas and water cannons. A number of protesters were detained.

Police said in a statement that some masked rioters had damaged shops, committed arson and placed nails on roads. They also said they halted two approved pro-democracy rallies due to the mayhem.

In one of those rallies, thousands gathered at a public square overlooking the city’s harbor to press for the passage of a U.S. bill that could place diplomatic action and economic sanctions on Hong Kong over human rights violations. U.S. lawmakers have passed the bill, which still needs Senate backing.

The chaos Saturday underlined the depth of anger in protests that began in early June over a now-shelved plan to allow extraditions to mainland China but have since swelled into a movement seeking other demands, including direct elections for the city’s leaders.

A move last month by Hong Kong’s leader, Carrie Lam, to invoke emergency powers to impose a face mask ban was slammed by protesters as crimping their right to assemble.

The increasingly violent unrest, with more than 3,000 people detained since the protests began, has hurt the reputation of one of the world’s top financial hubs. The city has slipped into recession for the first time in a decade as it grapples with the turmoil and the impact from the U.S.-China trade war.

The civil disobedience has posed a big challenge for Beijing, which vowed Friday to prevent foreign powers from sowing acts of “separatism, subversion, infiltration and sabotage” in Hong Kong.

In a Communist Party document released after its Central Committee meeting this past week, Beijing said it would “establish and strengthen a legal system and enforcement mechanism” to safeguard national security in Hong Kong.

Hong Kong, which has a separate legal system from mainland China, has tried to enact anti-subversion legislation before, only to have the measure shelved amid formidable public opposition. Beijing may be indicating it is preparing to take matters into its own hands by having the National People’s Congress issue a legal interpretation forcing the enactment of such legislation.