Hong Kong (CNN) More than 1 million protesters took to the streets of Hong Kong Sunday, organizers said, to oppose a controversial extradition bill that would enable China to extradite fugitives from the city.

The mass of protesters would be the largest demonstration since the city was handed back to China in 1997. Civil Human Rights Front, the group that organized the protests, said 1.03 million people marched -- a figure that accounts for almost one in seven of the city's 7.48 million-strong population.

Hong Kong Police estimated the number of protesters closer to 240,000.

Critics say the bill will leave anyone on Hong Kong soil vulnerable to being grabbed by the Chinese authorities for political reasons or inadvertent business offenses and undermine the city's semi-autonomous legal system.

The bill has caused political gridlock, outcry among the city's usually pro-conservative business community, and even physical scuffles in the city's legislature, as well as criticism of the Hong Kong government by the United States and European Union.

-- such as Taiwan, Macau and mainland China. Lawmakers have said the The government says the bill is designed to plug loopholes in current law by allowing Hong Kong to decide on a case-by-case basis whether or not to send fugitives to territories where it doesn't have formal extradition deals-- such as Taiwan, Macau and mainland China. Lawmakers have said the guarantee of a fair trial will not be written into the bill.

Protesters waved placards and wore white -- the designated color of the rally. "Hong Kong, never give up!" some chanted.

Sunday afternoon, protesters gathered at Victoria Park in central Hong Kong, waving placards and wearing white -- the designated color of the rally. "Hong Kong, never give up!" some chanted.

Other protesters were heard chanting "step down," "shelve the evil law," "anti extradition to China," and called for Carrie Lam, the chief executive of Hong Kong, to step down, as the marchers made their way along the 3-kilometer (1.86-mile) route to the Legislative Council in the Admiralty business district.

At least seven people were arrested, the police posted to Twitter

At around 7:30 p.m. in Hong Kong (7:30 a.m. ET), five to six men with masks planned to occupy a main road in the city, Hong Kong Police said on Twitter.

Police said they used pepper spray on the protesters before they escaped the area. Officers urged protesters to disperse.

The protest was mostly peaceful during the day, but it turned violent overnight, with police trying to clear protesters with batons.

Thousands also gathered to protest the extradition bill in cities across Australia on Sunday. Similar marches were planned in other cities around the world, Hong Kong political group Demosisto said in a statement.

At about 10.30 p.m. (10.30 a.m. ET), organizers announced that the protest had ended. CNN journalists on the ground said the bulk of the protesters had dispersed by then, leaving a number of people milling around the Legislative Council.

Late Sunday, the government of Hong Kong released a statement acknowledging the ongoing protests across the island but reiterating the contested bill is still scheduled to resume debate June 12.

"We urge the Legislative Council to scrutinize the Bill in a calm, reasonable and respectful manner to help ensure Hong Kong remains a safe city for residents and business," it said.

Murder of tourist

The case for the bill was expedited by a grisly murder case in Taiwan, where a 20-year-old Hong Kong woman was allegedly killed by her boyfriend while on holiday there. Currently, the suspect cannot be sent from Hong Kong to face justice in Taiwan.

In #HongKong, scores of protesters - including this family - gather in Victoria Park to take part in a march against the proposed #extradition law. pic.twitter.com/Qc61f6REEk — Kristie Lu Stout✌🏽 (@klustout) June 9, 2019

However, Taipei has already said it will refuse to cooperate with the new law if it puts Taiwanese citizens at risk of being extradited to China. The self-ruled island has previously seen citizens accused of crimes in countries that do not recognize Taiwan diplomatically being handed to Chinese custody , despite objections of Taipei.

Earlier this week, Chris Patten, the last British governor of Hong Kong, slammed the bill.

"People have known exactly why there shouldn't be an extradition agreement with China for years," Patten said in a video message Thursday. "The argument that it's better to have an extradition treaty than to abduct people illegally from Hong Kong -- are people really supposed to believe that?"

Protesters take part in a rally against the proposed extradition law on April 28, 2019, in Hong Kong.

Last month, representatives from the European Union met with Lam, the chief executive, and expressed concern over the bill. Members of the US Congressional-Executive Commission on China (CECC) have also spoken out against the bill, warning Lam it could "negatively impact the relationship between the United States and Hong Kong."

Unwanted and unneeded?

Business groups in Hong Kong usually take a neutral stance on contentious political issues. But this time they, too, have spoken out against the bill. In a bid to secure their support, the government has limited the scope of extraditable offenses -- but for some that is still not enough.

The American Chamber of Commerce in Hong Kong warned last week there were "too many uncertainties in fundamental sections of the proposed legislation" for it to be passed in its current form.

"Hong Kong is not ready to see this bill passed and we do not see why it should be rushed through when the loophole it seeks to address has existed for 20 years," the chamber said in a statement.

A woman holds a poster of Hong Kong Chief Executive Carrie Lam, against a proposed extradition law, before a candlelight vigil at Victoria Park in Hong Kong on June 4, 2019.

But government spokesman Matthew Cheung said the move was time sensitive.

"The suspect in the Taiwan murder case is serving sentences for other criminal offenses in Hong Kong but is expected to be released this October," Cheung said. "There is thus a pressing need to provide a legal basis for the assistance that we want to render to Taiwan, before the (legislature) goes into summer recess from mid-July to October."

Cheung did not address Taipei's concerns over the bill. Separately, Lam said it was "unfounded" to suggest the Hong Kong government "will just follow the instructions given by the Central Government and surrender whatever fugitives that the Central Government wants."

A US State Department spokesperson said Washington is "concerned by the Hong Kong government's proposed amendments to its Fugitive Offenders Ordinance, which would allow for individuals to be transferred to mainland China at the request of Communist Party authorities, and is closely monitoring the situation."

"Societies are best served when diverse political views are respected and can be freely expressed," the spokesperson said in a statement. "Continued erosion of the 'One country, Two systems' framework puts at risk Hong Kong's long-established special status in international affairs."

Fierce opposition

The extradition bill, particularly an attempt to fast-track it through Hong Kong's semi-democratic Legislature, has reinvigorated the city's flagging opposition movement after numerous setbacks.

Organizers claimed 130,000 people took part in a protest against the bill in April . While police gave the lower figure of 22,800, it was still the biggest protest since the 2014 Umbrella Movement, an ultimately unsuccessful protest over political reform which shut down parts of the city for months.

Photos: Massive Hong Kong vigil held 30 years after Tiananmen A candlelight vigil, held in Hong Kong's Victoria Park on Tuesday, remembered the victims of the 1989 massacre in Beijing's Tiananmen Square. Hide Caption 1 of 8 Photos: Massive Hong Kong vigil held 30 years after Tiananmen The annual candlelight vigil has been taking place in Hong Kong's Victoria Park since 1990. The vigil calls for the release of all dissidents, rehabilitation of the 1989 pro-democracy movement, accountability for the massacre, the end of one-party dictatorship and the start of a democratic China. Hide Caption 2 of 8 Photos: Massive Hong Kong vigil held 30 years after Tiananmen For many who lived in Hong Kong in 1989, the massacre quashed their hopes that a rapidly reforming China would also bring democracy to the city. "Young people in China were demanding democracy," Lee Cheuk-yan, one of the organizers, told CNN in 2017. "We felt that if they made it, it meant Hong Kong would not have to live under an authoritarian regime." The massacre forever changed the character of Hong Kong, Lee said. "In the past we were something of an economic city, but after 1989 we became a political city." Hide Caption 3 of 8 Photos: Massive Hong Kong vigil held 30 years after Tiananmen While attendance at the annual vigil has fluctuated — with some, particularly younger people, complaining that the focus on democracy in China ignores more pressing demands for reform in the city — key anniversaries have always brought massive numbers to Victoria Park. According to the Hong Kong Alliance in Support of Patriotic Democratic Movements in China, more than 200,000 people attended a commemoration in 2009, and 180,000 came out in 2014 for the 25th anniversary. Hide Caption 4 of 8 Photos: Massive Hong Kong vigil held 30 years after Tiananmen Tens of thousands filled Victoria Park on Tuesday, ignoring sweltering heat and threatening clouds overhead. Most wore black and almost all held candles overhead. The crowd chanted: "Demand accountability for the massacre! End one-party dictatorship! Build a democratic China!" Hide Caption 5 of 8 Photos: Massive Hong Kong vigil held 30 years after Tiananmen Students at the University of Hong Kong clean the "Pillar of Shame" statue, a memorial for those killed in the 1989 crackdown. Hide Caption 6 of 8 Photos: Massive Hong Kong vigil held 30 years after Tiananmen Students at the University of Hong Kong observe a minute of silence in front of the "Pillar of Shame" statue. Hide Caption 7 of 8 Photos: Massive Hong Kong vigil held 30 years after Tiananmen A Chinese paramilitary police officer stands guard in front of Mao Zedong's portrait on Beijing's Tiananmen Gate on Tuesday. Hide Caption 8 of 8

Fears over the bill -- and criticism from a broad swath of Hong Kong society -- echo 2003, when half a million people took to the streets to oppose the passage of an anti-sedition law. That legislation was shelved, but the issue has become such a hot-button topic in Hong Kong that -- despite promising to do so -- no governments since have attempted to introduce it.

Sunday's protest comes days after the 30th anniversary of the Tiananmen Square massacre , a pivotal moment that dashed hopes China would democratize before it took control of Hong Kong in 1997.

Hong Kong has commemorated the massacre with a candlelit vigil ever since, the only place on Chinese soil where mass remembrances are held. Organizers said more than 180,000 people joined a vigil in the city's Victoria Park on Tuesday , the largest such event since the 25th anniversary in 2014, which came in the politically fraught run-up to the Umbrella protests.

Correction: A previous version of this story misstated the number of people who participated in protests in Hong Kong on Sunday. The Civil Human Rights Front estimates there were 1.03 million protesters.