Thousands of Hong Kong residents braved sweltering heat on Sunday to protest against Beijing's tightening grip over the city as the former British colony marked the 21st anniversary of its return to Chinese rule.

The protestors included elderly people in wheelchairs, couples with sleeping toddlers and young residents, some of whom waved banners saying: "End one party rule; Against the fall of Hong Kong."

"Now the government is already siding with the Communist Party. Can Hong Kong see any universal suffrage in 20 or 30 year's time? I don't think so," said 13-year-old Joanna Wen, who was accompanied by her father.