HONG KONG — Thousands of protesters dressed in black on Sunday flooded Hong Kong's streets and surrounded a train station connecting the island to mainland China as part of an escalating movement to preserve the territory's independence.

Demonstrations kicked off last month in opposition to a proposed extradition bill that would allow for suspects to be sent to the mainland to face trial, but have since expanded into a broader repudiation of Beijing's growing influence.

The movement has sparked some of the largest demonstrations in the city's history, with as many as 2 million of Hong Kong's 7 million residents taking to the streets. Sunday's protests were calmer in comparison, with organizers estimating over 230,000 people in attendance.

"This is about the future of Hong Kong," protester Andy Chiu, 52, told NBC News Sunday.

"It is our right to protest, to express what we want," said Chiu, who had brought his son along with him. "We need to preserve it, and let the younger generations to know that this is their right, and this shall not be taken away from them in the future."

Sunday's march was the first significant demonstration since protests turned violent last Monday.

The march began on the harborfront promenade adjacent to museums and Hong Kong's walk of fame, where a moment of silence was held to acknowledge those who have suffered injuries throughout the campaign.

Chanting slogans and words of encouragement to their fellow citizens, demonstrators then headed west through a popular shopping destination dotted with luxury shops and toward a major rail hub where visitors from mainland China arrive.

That marked a change from previous routes.

Organizers said Sunday's aims were to reiterate the protesters' demands to the government and to give mainland visitors a firsthand look at their movement.

Protesters take part in a march to the West Kowloon railway station, where high-speed trains depart for the Chinese mainland, during a demonstration against a proposed extradition bill in Hong Kong on July 7, 2019. HECTOR RETAMAL / AFP - Getty Images

Lau Wing-hong, one of the organizers, said the rally would be peaceful.

"It is hoped that Hong Kong people can spread how Hong Kong people can march peacefully and bring the protest information back to the mainland to mainland visitors," Lau told Reuters.

However, hours after the march was expected to end, demonstrations continued. The gathering, considered illegal by police, resulted in clashes and arrests.

On Monday protesters smashed their way into the city's Legislative Council building, defacing the territory's emblem while installing a colonial flag featuring Great Britain's Union Jack in the upper-left-hand corner.

They were fought back by riot police who fired tear gas to disperse the crowds.

The incident was condemned by Hong Kong's chief executive Carrie Lam, who said the rule of law must be upheld.

Protesters have focused much of their ire on Lam, calling for her to step down even after she relented and suspended the proposed extradition bill indefinitely.

Protesters have said the bill would threaten the former British colony's semi-autonomous rule and have demanded it be scrapped permanently.

Hong Kong was allowed to maintain its own legal system for 50 years after being returned to China in 1997.

Unlike those in the mainland, Hong Kong residents can freely surf the internet and participate in public protests.

They have spent the last month exercising that right.

In addition to scrapping the bill, demonstrators are now demanding that authorities retract the description of the movement as a riot, drop all charges against protesters, investigate alleged abuses of power by the police force and replace the governing Legislative Council with a more democratic body.

The demonstrations aren't only fueling tensions between China and Hong Kong, but also with Britain.

Beijing has accused the U.K. of bolstering the protests by supporting the pro-democracy movement in Hong Kong.

Liu Xiaoming, China's ambassador to London, said last week that Britain was still acting as Hong Kong's colonial master and must take its "hands off" the territory and "show some respect."

Veta Chan reported from Hong Kong and Linda Givetash reported from London.