HONG KONG — Violence erupted once again in Hong Kong Sunday as thousands of protesters marched through the Chinese territory in defiance of a police ban.

Hundreds of protesters targeted a government office complex in the downtown area, throwing bricks and Molotov cocktails through police barriers.

Police responded by firing volleys of tear gas and rubber bullet rounds. They also used a water cannon to spray blue-dyed water, in a repeat of confrontational scenes that have marked the last few weeks of the demonstrations.

Protesters react as police fire water cannons outside the government headquarters in Hong Kong on Sunday. ISAAC LAWRENCE / AFP - Getty Images

Protests have roiled the semi-autonomous Chinese city for months, sparked by a controversial extradition bill that would have allowed Hong Kong residents to be sent to mainland China for trial.

The bill has since been withdrawn by Hong Kong leader Carrie Lam, but the protests have continued after morphing into a broader rejection of China's growing influence and its impact on the rights and freedoms of Hong Kong citizens.

Thirty-four-year-old banker, Jess, who did not want to provide her last name out of fear of prosecution, said the protest movement is now about “fighting for our future.”

“If Carrie Lam decided to withdraw [the bill] back in June, maybe the movement would end,” she said.

“After all the unreasonable beatings and massive arrests of protesters and citizens, we need to step up to fight against this government. A government who works against its people.”

An anti-government protester prepares to throw a Molotov cocktail during a demonstration in Hong Kong, China on Sunday. TYRONE SIU / Reuters

The ongoing unrest is seen as an embarrassment to China, which has accused foreign powers of fomenting the protests.

Many in Hong Kong worry that if the demonstrations persist to Oct. 1, the 70th anniversary of the founding of the People’s Republic of China, it could incite a harsh reaction from leaders in Beijing who will not want to see nationwide celebrations marred by dissent.

At least 1,300 people have been arrested since June, but the demonstrations show no signs of letting up in the face of a robust police response.

Protesters are pushing for the government to meet four demands beyond the withdrawal of the extradition bill: the resignation of Carrie Lam, the release of all those arrested, an inquiry into alleged police brutality and the right for fully democratic elections.

Asked why they continue to protest, Jo, 23, a university student who also preferred not to reveal his last name, told NBC News: “One down, four more to go. We have five demands, all needed to be answered, not one less."

“This is not police doing their job, this is police abusing their power,” he added.

Hong Kong police had previously turned down a request to hold Sunday's march and warned that anyone attending could face imprisonment, but demonstrators were undeterred.

Earlier on Sunday a mixed crowd of protesters dressed in black and wearing masks, along with families with children, spilled into the roads of the Causeway Bay shopping belt and marched for over a mile to the central business district.

Some in the crowd sang the unofficial national anthem, “Glory to Hong Kong,” and chanted “No rioters, only a tyrannical regime.”

Others waved U.S. flags, sang the national anthem and held up banners asking President Donald Trump to “liberate Hong Kong.”

#HongKong citizens singing the #US national anthem while marching in the “unauthorised protest” originally organised by Civil Human Rights Front, but rejected by #HongKongPolice #Hongkongprotest #antiELAB pic.twitter.com/zlfuALwwot — Veta Chan (@veta_chan) September 15, 2019

NBC News also saw some protesters tearing down pro-China banners in front of Carrie Lam's office.

On Saturday, pro-democracy protesters and supporters of the central government in Beijing clashed at a Hong Kong shopping mall and several public places. Police arrested more than a dozen people and hospital authorities said 25 were injured.

Police fire tear gas trying to disperse anti-government protesters near Causeway Bay station in Hong Kong, China on Sunday. TYRONE SIU / Reuters

Thousands of people carried lanterns with pro-democracy messages in public areas and formed illuminated human chains in a peaceful demonstration on two of the city's peaks on Friday.

Veta Chan and Mac William Bishop reported from Hong Kong. Yuliya Talmazan from London.