HONG KONG — Hundreds of thousands of demonstrators crammed into Hong Kong's streets on Sunday, their chants echoing off high-rises, in a mass show of support for a protest movement that shows no signs of flagging as it enters a seventh month.

Chanting “Fight for freedom” and “Stand with Hong Kong,” a sea of protesters formed a huge human snake winding for blocks on Hong Kong Island, from the Causeway Bay shopping district to the Central business zone, a distance of more than 1 1/4 miles. It was one of the biggest rallies in months.

Crowds were so large and dense that the march ground to a standstill at times. Protesters spilled into narrow side streets, crying “Revolution in our times.”

Organizers said 800,000 people participated, while officials put the figure at 18,000.

Protesters march into the night in Hong Kong on Sunday. Dake Kang / AP

One protester crawled part of the route prostrated on her hands and knees, dragging bricks and empty soda cans behind her. It was an apt metaphor for the pro-democracy movement, which has become a long-haul push to preserve Hong Kong's freedoms that make it unique among China's cities.

“This is just the beginning. We have a long way to run,” said another demonstrator, Louisa Yiu, an engineer.

Many marchers held up five fingers to press the movement's five demands. They include democratic elections for Hong Kong's leader and legislature and a demand for a probe of police behavior during the six months of continuous protests.

Marchers said they hoped the huge turnout might help win concessions from the government of Chief Executive Carrie Lam. Protesters spanned generations. One man's young son marched in his Spiderman suit.

“We need to encourage our Hong Kongers. Our government is a failure and the members inside refuse this truth,” 40-year-old clerk Cindy Siu told NBC News.

“The government ignores our public opinion and keeps on surprising the young kids. They’re our city’s future, our future.”

Anti-government protesters march Sunday in Hong Kong. Anthony Kwan / Getty Images

Marchers said protesting has become part of the fabric of their lives since demonstrations erupted in June against a now-withdrawn government measure that would have allowed criminal suspects to be sent for trial in Communist Party-controlled courts in mainland China.

The protests have since snowballed into a broad, sustained anti-government movement, presenting the communist leadership in Beijing with a major headache and battering Hong Kong's economy.

Police in riot gear deployed in numbers on the edges of the march. Earlier in the day, they arrested 11 people and seized a cache of weapons, including a firearm with more than 100 bullets. Police said the suspects apparently planned to use the weapons during the protest to frame police, who have been accused of using excessive force against the protesters.

Violence was limited, with a bank vandalized and police reporting that gasoline bombs were thrown outside the High Court.

Rally organizer Eric Lai had called for police restraint and for no use of tear gas.

Protesters look on from Pedder Street in Central following a pro-democracy rally from Victoria Park to Chater Road in Hong Kong on Sunday. Anthony Wallace / AFP - Getty Images

“We hope this will be a signature for our movement after six months to show to Carrie Lam as well as to the world that people are not giving up. People will still fight for our freedom and democracy,” Lai said.

Authorities, who have liberally used tear gas, water cannons and rubber bullets at previous demonstrations, say force has been necessary to disperse hard-core protesters who have battled riot officers, vandalized shops and thrown gasoline bombs.

Police banned mass marches as protests turned increasingly violent, but relented and allowed Sunday's march after a few weeks of relative peace.