HONG KONG (AP) — Tens of thousands of Hong Kong residents marched Tuesday through the streets of the former British colony to push for greater democracy in a rally fueled by anger over Beijing’s recent warning that it holds the ultimate authority over the southern Chinese financial center.

Organizers expected the crowd to swell to at least 150,000 and were hoping as many as 500,000 would turn out to call for reforms allowing residents to elect their leader.

The protest comes days after nearly 800,000 residents voted in a mock referendum aimed at bolstering support for full democracy.

The peaceful crowds carried banners and posters urging democracy as they marched in sweltering heat through skyscraper-lined streets to the financial district. Some chanted, “Our own government, our own choice,” while others called for the city’s leader, Chief Executive Leung Chun-ying, to step down.

Some groups along the protest route sang a Cantonese version of “Can you hear the people sing?” from the musical adaptation of Victor Hugo’s novel “Les Miserables.” The song has become an anthem for Hong Kong’s pro-democracy movement.

July 1, a public holiday marking the handover of power from London to Beijing in 1997, has become an annual day of protest. This year a focal point for demonstrators’ anger is a policy document, or “white paper,” released last month by China’s Cabinet that said Hong Kong’s high degree of autonomy is not inherent but is authorized by the central government.

“After seeing the white paper’s content, we should be worried,” said Jeff Kwok, 28, as he waited at the rally’s starting point in Victoria Park. “The central government, they’re trying to tell the Hong Kong people that they are the host country and Hong Kong is just one of their regions. They’re trying to tell us they have absolute power to rule us.”

Kwok, who works at an export firm, complained that Beijing doesn’t’ respect the principle of “one country, two systems” under which Hong Kong is allowed to retain civil liberties unseen on the mainland and control over much of its own affairs.

Another protester, Kennie Chan, lamented that Beijing was less restrained now in exerting its influence over Hong Kong.

“In the past, it seemed like they were doing it step by step, but now, it’s obvious that they cannot stand Hong Kong people. We are not obedient anymore, and are resisting more and more,” said the 30-year-old, who works as a stage manager.

Ahead of the rally, a small group of protesters burned a copy of the white paper outside of a ceremony attended by officials to mark the handover.

China’s Communist leaders have pledged to start allowing Hong Kongers to vote for the city’s leader in 2017, though they insist that candidates be vetted by a Beijing-friendly committee like the one that has hand-picked all leaders since the handover.

But pro-democracy activists, encouraged by the strong turnout for their informal referendum, vow to shut down the city’s financial district with a mass sit-in if the government fails to come up with electoral reforms that meet international standards.

Leung tried to soothe tensions, saying in a speech that he will do his “utmost to forge a consensus in the community and work together toward the goal of implementing universal suffrage” on schedule.