HONG KONG (CNN) -- Thousands of demonstrators bracing for the possibility of a police crackdown packed streets in the heart of Hong Kong early Tuesday.
Protesters had protective goggles and plastic rain coats on hand as they camped out on the main thoroughfare leading into the city's central business district around 3 a.m. Tuesday, about 24 hours after officers had used tear gas and pepper spray on the crowd.
"They're all ready just in case there is any sort of move by the Hong Kong police," CNN's Andrew Stevens reported.
At least 52 people have been injured so far in the largely student-led protests, which flared into violence starting Sunday, a Hong Kong government spokeswoman said.
Both protesters and police have been calling for calm, Stevens said. And at the moment, the situation is peaceful.
A large orange banner hanging over the protesters, Stevens reported, says "freedom in the midst of a storm."
Demonstrators calling for the resignation of Hong Kong's chief executive say they're not going anywhere. Authorities also don't seem to show any sign of backing down; officials in Hong Kong and China say it's an illegal gathering.
"The next step really at this stage is very difficult to predict," Stevens said.
Demonstrations began in response to China's decision to allow only Beijing-vetted candidates to stand in the city's 2017 election for the top civil position of chief executive. Protesters say Beijing has gone back on its pledge to allow universal suffrage in Hong Kong, which was promised "a high degree of autonomy" when it was handed back to China by Britain in 1997.
Numbers swelled over the weekend and a police crackdown on Sunday -- involving tear gas, batons and pepper spray -- left more than 40 people injured. Protesters began calling for the resignation of current Chief Executive C.Y. Leung.
The protests have brought widespread disruption to the heart of one of Asia's biggest financial centers, blocking traffic on multilane roads and prompting the suspension of school classes.
The government adopted a more conciliatory approach Monday, saying it had withdrawn riot police from the protest areas. It urged people to disperse and allow traffic to return to the roads.
But the protesters, rallying against what many see as the growing influence of the Chinese Communist Party on the way Hong Kong is run, are so far refusing to budge.
CNN's Ivan Watson, at the scene, described it as a "sea of humanity," the biggest crowd he had witnessed since protests began last week.
"The young people -- predominantly 21, 22 years old -- have been chanting out here, repeating the word 'hah toih,' meaning 'resign,'" Watson said, against a backdrop of chanting and waving cellphones.
"As long as there's one person that's still out here on this highway, I'm going to be here," a young woman named Nikki told CNN at the main protest site, near the government headquarters, where thousands of people were gathered on Monday.
Police action shocks residents
The large-scale demonstrations now taking place grew out of student-led boycotts and protests that began last week. The demonstrations increased in size over the weekend after gaining the support of Occupy Central with Love and Peace, a protest group that was already planning to lead a campaign of civil disobedience later this week against the Chinese government's decision.
Images of heavy-handed treatment of protesters by police shocked many residents of Hong Kong, where large-scale, peaceful protests are common, but police crackdowns are not.
Watson -- who himself was enveloped in a cloud of stinging tear gas Sunday -- said protesters and police appeared unused to the method of crowd control.
"Both sides were appealing for calm, and then the tear gas just exploded in the midst of everybody," he said. "People here have never been hit by tear gas before and it comes as quite a shock to them -- even the use of pepper spray. ... This is a big shock for a city that is famed for its law and order."
The strong police response appeared to stir thousands more people into joining the demonstrations, swelling the ranks of protesters around the government headquarters and starting new rallies in other key areas of the city, including the densely populated district of Kowloon, which sits on the opposite side of Victoria Harbor from Hong Kong Island.
"They shouldn't have used tear gas," said Brian Lo, 37, who works in human resources and wasn't protesting. "This made people angry."
CNN's Andrew Stevens, among the protesters, said crowd numbers had grown after the riot police withdrew.
"It's swelling every five minutes or so. There does seem to be a significant increase in this. They're also starting to chant much more often too. We're hearing different chants -- the most common refrain has been 'Stand down, C.Y. Leung,'" Stevens said.
Despite the government's announcement that it had pulled riot police back from the protest sites, smaller numbers of officers remained on guard on the sidelines of the main protest area.
Aside from the clashes with police, the protesters have remained overwhelmingly peaceful. People have been picking up trash left at the protest sites, handing out bottles of water and encouraging police officers to put down their weapons and join the demonstrations.
In the face of tear gas and pepper spray, demonstrators have used goggles, homemade masks and umbrellas to protect themselves.
The abundance of umbrellas among the crowds, shielding people from both tear gas and the fierce glare of the sun, has prompted many social media users to dub the movement the "umbrella revolution."
'We had to use force'
Fears nonetheless remain about the possibility of a heavier crackdown from authorities. Both the Chinese and Hong Kong governments have said they consider the protests to be unlawful.
Leung has said police have acted with the greatest possible restraint in dealing with the protesters. At least 12 police officers were among the 47 people injured, authorities said.
"We gave them enough of a chance to leave, and this included warnings," Assistant Police Commissioner Cheung Tak-keung said of protesters at a news conference Monday. "But when they failed, we had to use force."
Police fired a total of 87 tear gas canisters on Sunday night, he said.
In an indication authorities don't expect the demonstrations to end soon, the Hong Kong government said it was canceling the city's annual fireworks display on Wednesday, China's National Day, because of the protests.
What will Beijing do?
Some commentators say they see little hope of compromise between the committed protesters and the Chinese Communist Party, which remains notorious for its ruthless suppression of pro-democracy protests in Beijing's Tiananmen Square in 1989.
"I see no way the Chinese government can tolerate what is happening in HK. Greatly fear this will end badly," tweeted Mike Chinoy, a senior fellow at the U.S.-China Institute at the University of Southern California, who covered the Tiananmen crackdown for CNN.
Pro-democracy activist and former legislator Martin Lee told CNN's Watson that China had troops stationed in Hong Kong who could clear the streets if ordered to.
"But Hong Kong people, I think, many of them would not be scared. I certainly would not be scared. And I've said it before and I say it again, if I see a tank from the Chinese troops in Hong Kong, I would get myself a bicycle and stand right in front of it," Lee said.
Hua Chunying, a spokeswoman for the Chinese Ministry of Foreign Affairs, said Monday that Beijing fully believes in and firmly supports the Hong Kong government's "ability to handle the situation in accordance with the law."
Chinese authorities appeared to be taking steps to restrict the flow of information into the mainland about what was happening in Hong Kong. State media gave little coverage to the story, and it appeared censors had blocked access to Instagram after images of the protests flooded the photo-sharing app.
Hong Kong citizens enjoy a range of civil liberties, including rights to free speech and assembly, that are severely restricted in mainland China.
The U.S. Consulate in Hong Kong said Monday that the United States "strongly supports Hong Kong's well-established traditions and Basic Law protections of internationally recognized fundamental freedoms." (The Basic Law, which serves as a de facto constitution, was written in the lead-up to the 1997 handover of sovereignty from Britain to China.)
It added that it doesn't "take sides in the discussion of Hong Kong's political development, nor do we support any particular individuals or groups involved in it."
A UK Foreign Office spokesman said Britain believed Hong Kong's prosperity and security were "underpinned by its fundamental rights and freedoms, including the right to demonstrate."
"It is important for Hong Kong to preserve these rights and for Hong Kong people to exercise them within the law," the spokesman said. "These freedoms are best guaranteed by the transition to universal suffrage."
CNN's Esther Pang, Vivian Kam, Anjali Tsui, Simon Harrison, Euan McKirdy, Felicia Wong, Ivan Watson, Andrew Stevens, Chieu Luu, Elizabeth Joseph, David McKenzie, Steven Jiang, Katie Hunt and Steve Almasy contributed to this report.