Hong Kong leader Carrie Lam said Monday she would "seriously reflect" on a stunning landslide victory by pro-democracy candidates in the city's local election that was a clear rebuke of how she has handled violent protests that divided the semi-autonomous Chinese territory.

Pro-democracy candidates swept nearly 90% of 452 district council seats, which will help it take unprecedented control of 17 out of 18 district councils, said Wu Chi-wai, head of the biggest pro-democracy bloc.

Sunday's results could force the central government in Beijing to rethink how to handle the unrest, which is now in its sixth month. The district councils have little power, but the vote became a referendum on public support for the protests.

"It's nothing short of a revolution," said Willy Lam, a political expert at the Chinese University of Hong Kong. "It's a sound repudiation of the Carrie Lam administration and shows the silent majority are behind the demands of the protesters."

Carrie Lam, the embattled leader of the territory, acknowledged that some people viewed the results as a representation of public "dissatisfaction with the current situation and the deep-seated problems in society."

She said the government "will listen to the opinions of members of the public humbly and seriously reflect" on them.

The pro-democracy camp hailed its astounding gains as a victory for the people and said Lam and Beijing must now seriously heed protesters' demands, which include free elections for the city's leader and legislature as well as an investigation into alleged police brutality.

"We are only vehicles used to reflect the people's concerns," said Wu.

Beijing, which blames foreign powers for fomenting the unrest in Hong Kong, has showed no signs that it might soften its stance on the former British colony, which was returned to China in 1997.

Chinese Foreign Minister Wang Yi told reporters during a visit to Tokyo that Hong Kong will always be part of China, no matter the election outcome.

"Any attempts to destroy Hong Kong or harm Hong Kong's stability and development cannot possibly succeed," he said.

But the results will add new pressure on Lam. Some pro-establishment candidates have already pointed fingers at her for their loss, while the pro-democracy camp said she should quit.

"I would say directly to Carrie Lam, do not squander this opportunity. Don't waste this chance ... the window has been opened for you," said British politician David Alton, one of the independent election monitors.

A record 71% of Hong Kong's 4.1 million registered voters cast ballots in the city's only fully democratic elections, well exceeding the 47% turnout in the same poll four years ago.

The largest pro-establishment political party suffered the biggest setback, with only 21 of its 182 candidates winning. Its chairwoman, Starry Lee, said the government must review its response to the crisis and do more to heal the divisions in society.

Many pro-Beijing political heavyweights were trounced, including controversial lawmaker Junius Ho, who is reviled by protesters for supporting a bloody mob attack on demonstrators in July. Ho was stabbed with a knife during campaigning this month.

The winners included many youth activists and a candidate who replaced activist Joshua Wong, the only person barred from running in the election. Protest rally organizer Jimmy Sham, who was beaten by hammer-wielding assailants last month, also triumphed, as did a pro-democracy lawmaker who had part of his ear bitten off by an assailant.

Celebrations broke out outside polling stations overnight when results were announced. At lunchtime Monday, dozens of supporters held a victory rally in a business district. A woman popped a champagne bottle and poured drinks for everyone.

"This is historic. As our city plummets from being semi-autonomous to semi-authoritarian, we react by showing what's democracy in action," Wong tweeted.

More than 5,000 people have been arrested in the unrest that has contributed to Hong Kong's first recession in a decade.

Supporters from both sides of the divide hope the election will pave a peaceful way out after months of pitched battles between protesters and police, capped by a university siege this month. An estimated 30 protesters, fearing arrest, are still hiding inside the Polytechnic University.

Riot police blocked hundreds of activists from advancing into the campus Monday evening, and a pro-democracy supporter appealed for calm. They want an end to the police siege but police said they will send a team of negotiators into the campus to find and coax the holdouts to surrender.

"With the mandate from the Hong Kong people, protesters expect concessions from Beijing, but those concessions won't be coming. Confrontations may intensify," warned political analyst Lam.

The victory will see the pro-democracy camp secure 117 seats in the 1,200-member pro-Beijing panel that elects the city's leader. It will bolster their influence, as the bloc usually has over 300 supporters on the panel but still falls short of the majority.

The turmoil started in June over a now-abandoned extradition bill that many viewed as a sign of creeping Chinese control over Hong Kong, but protesters have since expanded their demands.