Protesters march to the West Kowloon railway station during a demonstration in Hong Kong on July 7, 2019.

Tens of thousands rallied in a large Hong Kong suburb on Sunday, driven by abiding anger at the government's handling of an extradition bill that has revived fears of China tightening its grip over the former British colony and eroding its freedoms.

Clashes broke out as protesters hurled umbrellas and plastic bottles at police who retaliated by firing pepper spray amid chaotic scenes inside a shopping mall that houses some of the world's biggest luxury brands.

Most of the demonstrators dispersed shortly afterward as a small group sang the Christian hymn "Sing Hallelujah to the Lord", which has emerged as the unlikely anthem of the protests.

Millions have taken to the streets in the past month in some of the largest and most violent protests in decades over an extradition bill that would allow people to be sent to mainland China for trial in courts controlled by the Communist Party.

Protesters marched in sweltering heat of about 32 degrees Celsius (89.6 F) in Sha Tin, a town between Hong Kong island and the border with China, extending the demonstrations outward from the heart of the financial center into surrounding districts.

"These days there is really no trust of China, and so the protesters come out," said Jennie Kwan, 73. "Didn't they promise 50 years, no change? And yet we've all seen the changes. I myself am already 70-something years old. What do I know about politics? But politics comes to you."

Hong Kong returned to Chinese rule in 1997 under a "one country, two systems" formula that guarantees its people freedoms for 50 years that are not enjoyed in mainland China, including the liberty to protest and an independent judiciary.

Beijing denies interfering in Hong Kong affairs, but many residents worry about what they see as an erosion of those freedoms and a relentless march toward mainland control.

Hong Kong's embattled leader, Carrie Lam, has said the extradition bill is "dead", but opponents say they will settle for nothing short of its formal withdrawal.

Some protesters on Sunday waved banners appealing to U.S. President Donald Trump to "Please liberate Hong Kong" and "Defend our Constitution". Such scenes are certain to rile Beijing, which has been angered by criticism from Washington and London over the controversial bill.

Others waved British and American flags, while banners calling for Hong Kong's independence billowed in the sultry breeze from makeshift flagpoles.

One placard featured a picture of Chinese leader Xi Jinping with the words: "Extradite to China, disappear forever."

Chants of "Carrie Lam go to hell!" rang through the crowd, gathered well away from the island heart of the financial center which has witnessed the largest and most violent demonstrations over the past month.

Organizers said around 115,000 attended Sunday's rally. Police put the number at 28,000 at its peak.