HONG KONG—As pro-democracy rallies spread across Hong Kong on Monday, the government offered minor concessions and police defended the use of tear gas against protesters over the weekend.
Tens of thousands of people stretched across Hong Kong Island's main shopping and business districts and across Victoria Harbour into Kowloon. Newcomers joined the protests, which took on an air of spontaneity, growing as the day progressed with marchers walking and sitting on the city's normally traffic-choked roads. (Read The Wall Street Journal's live updates on the protests here.)
Few police and almost none wearing riot gear were seen near the protesters, who were inundated with food, water and protective gear by supporters. There appeared to be no central organizing authority. "If I must name a leader of the movement, it is Hong Kong itself," said Amy Wong, a university student who said she joined protests out of anger at the tactics used by police.
The protests stayed peaceful and there has been no serious damage reported, even during the confrontations with police. On Monday morning, protesters bagged garbage from the night before, sorting plastic bottles for recycling. Protesters started calling their quest the Umbrella Revolution for the umbrellas they carried to deflect both pepper spray and the hot sun and were decorating them with phrases such democracy and freedom.
The protests are driven by Beijing's decision to impose limits on how Hong Kong elects its leader. But after the police repeatedly used tear gas against protesters on Sunday, support for the protests grew among Hong Kong residents angry over tactics not seen in the city for nearly a decade.
Throughout the day, the crowds erupted in spontaneous chants calling for the resignation of Hong Kong Chief Executive Leung Chun-ying, whom they see as responsible for both the election limits and the use of force on Sunday. Protest leaders and pro-democracy lawmakers also called for Mr. Leung to quit. Legislator Alan Leong said his coalition was drafting a motion for impeachment of Mr. Leung.
"We call upon the chief executive to resign. It's the only way he can beg for forgiveness," Mr. Leong told reporters.
The size of the protests and their peaceful nature underlines the dilemma for Beijing, which doesn't want other parts of China to follow Hong Kong's path, but would have trouble justifying a tough crackdown on the protesters.
Hong Kong's financial sector was hit by the protests Monday. Stocks fell 1.9%, hitting their lowest level in 2½ months and 23 banks closed more than 40 branches, offices or cash machines. Accounting firm KPMG LLG told its 1,800 employees in affected offices to stay home while the Hong Kong Monetary Authority, the city's de facto central bank, said it activated its own contingency plan and was ready to inject liquidity into the system. Markets operated normally on Monday.
Chief Secretary Carrie Lam, the city's No. 2 government official, went back on a statement she made Sunday that the process geared at approving Beijing's plan on elections was moving ahead swiftly. Instead, she said the city would delay the process. But she also said it would be unrealistic to ask Beijing to reverse its decision.
Beijing has agreed to grant the city's residents the right to vote starting in 2017 but only for candidates approved by a committee made up of 1,200 largely pro-Beijing, pro-business members. Currently the committee picks the chief executive without a popular vote.
The process still officially has several months to go, with another around of public consultations and a vote planned in the city's legislature. Protesters are calling for the process to start over and for Hong Kong's people to get full control over selecting their next leader.
Beijing has taken a hard line over the dispute over democracy in Hong Kong, issuing warnings to protest organizers, including students and the activist group called Occupy Central. At a briefing at China's Foreign Ministry, spokeswoman Hua Chunying, asserted Beijing's control over the city. "As we have always maintained, Hong Kong is China's Hong Kong," she said.
"We firmly oppose external forces supporting illegal activities, such as the Occupy Central movement," she said, a reference to a view of Hong Kong as a potential base for foreigners to exercise influence behind the scenes that could hurt China.
The White House on Monday urged authorities in Hong Kong to respond to pro-democracy protests with restraint. "We believe that an open society with the highest possible degree of autonomy, and governed by the rule of law, is essential for hong Kong's stability and prosperity," White House spokesman Josh Earnest said.
Mr. Earnest said the U.S. is closely watching the protests. "We support the aspirations of the Hong Kong people," he said.
Police came under strong criticism for their tactics on Sunday and early Monday. As crowds grew at the city's government headquarters, police blocked entrances. The result was the protest expanded to fill the city district of Admiralty. After police used tear gas, the protests spread to two shopping districts, Causeway Bay and Mong Kok.
Several security experts said police mishandled the situation.
"They really shouldn't have used any tear gas at all because ultimately it only had the effect to annoy people; the crowds were peaceful," said Julian Russell, a security consultant who worked on the police force when Hong Kong was under British rule.
In a news conference Monday, Assistant Police Commissioner Cheung Tak-keung said the decision to use tear gas and pepper spray on Sunday was made after some protesters used violence to breach police lines. He said the police had no alternative and described the option as "minimum force."
"Police respect citizens' right to use peaceful, rational, legal means to protest. But some protesters used violence to push through the police defense line, which we strongly condemn," Mr. Cheung said.
The protests began with a weeklong student boycott and rallies that led to the first battle with police on Friday night. On Sunday, the group called Occupy Central, which had pledged to disrupt the city's main business district if democratic reforms were blocked, joined in.
But by Monday, it appeared clear that protest groups were forming on their own. Occupy Central organizer Chan Kin-man said he was impressed with the spontaneity and resolve of the protesters. "The people outside, on the street, they are leaderless," he said.
Protesters used social-media sites to move protesters and supplies. Messages such as "Water and goggles are needed in Admiralty" brought a deluge of supplies, sometimes by motorcycle. Among the supplies were the now- ubiquitous umbrellas, used to deflect pepper spray and also to block the hot sun.
Protesters were downloading FireChat, which allows communication via Bluetooth if telecom networks are shut down.
The protests have been largely peaceful and there has been no serious damage reported. On Monday morning, protesters bagged garbage from the night before and sorted plastic bottles for recycling.
Monday began with a small number of exhausted protesters scattered in the city. At lunch hour, supporters swelled their numbers in three districts. Many stayed while others brought supplies. Ray Chung, an accountant, brought a box of bottled water and some bread to support protesters on his lunch hour. "I can't go on strike as my firm is too small," he said. "So I do this as a way of showing my support."
This week is a major shopping week in Hong Kong because of a weeklong holiday in mainland China, and October is the second biggest month of the year for retailers. Sales have been weak this year amid China's economic slowdown and crackdown on corruption. Data released Monday showed that Hong Kong retails sales were up 3.4% in August from a year earlier, but sales of jewelry, watches and valuable gifts, a key sector for Chinese tourists, fell 6.1%
The city's political turmoil will "add salt to the wound" of Hong Kong's retail sector, according to Raymond Yeung, a senior economist at ANZ.
—Prudence Ho in Hong Kong and Bob Davis in Beijing contributed to this article.
Leaderless' gatherings erupt across town amid anger at tear-gas tactics.