Hong Kong's new Beijing-backed leader has been sworn in amid rising public discontent over widening inequality and lack of full democracy in the semi-autonomous southern Chinese financial centre.
Tens of thousands of people are expected to take to the streets later on Sunday in an annual protest that is an occasion for ordinary people to air their grievances over a range of issues.
Al Jazeera's Rob McBride, reporting from Victoria Park in Hong Kong, where protesters had begun to gather, said the annual event is where various political groups come together. "If you have a grievance, you come out on this day to air those grievances."
"It has to be said, though, given the events of what has been taking place today with the new chief executive, more people have come out than usual."
Leung Chun-ying took office in a morning ceremony overseen by Chinese President Hu Jintao, becoming Hong Kong's third chief executive since more than a century of British colonial rule ended and China regained control of the city 15 years ago.
There were sporadic scuffles between demonstrators and police outside the convention centre where the event took place.
A demonstrator who tried to interrupt Hu as he began his address was bundled away by security officials.
The man, one of the guests invited to the inauguration, waved a small flag and yelled slogans calling for China's leaders to reverse their condemnation of the brutal June 4, 1989 crackdown on protesters in Tiananmen Square.
He also called for an end to one-party rule in China.
Hu took no notice and continued to read his speech, but the incident marred what was supposed to be a carefully orchestrated visit.
Leung, a police officer's son and self-made millionaire, replaces career bureaucrat Donald Tsang, who took office in 2005 and is barred from another term.
The 57-year-old takes over Hong Kong's top job amid swelling public anger over a yawning income gap, skyrocketing property prices and rising unease about mainland China's growing influence.
A protester interrupted the inauguration ceremony, yelling slogans against the Tiananmen Square crackdown [Reuters]
"We will focus our energies on major and pressing issues," said Leung, who outlined plans to even out Hong Kong's widening inequality.
He vowed to provide more affordable housing and land for property development, though he also said "there is no need for a major reversal of policy".
Calls for democracy have been catalysed by the way in which Leung got his job and by corruption scandals surrounding his predecessor.
Leung was chosen as chief executive in March, winning 689 votes from a 1,200-seat committee of business elites who mostly voted according to Beijing's wishes.
Hong Kong's 3.4 million registered voters, who can vote for neighbourhood councillors and half of all politicians, had no say.
Pro-democracy activists are gathering for an annual march that is expected to draw tens of thousands people.
The yearly event began in 2003, when half a million people turned out to protest anti-subversion legislation that was later shelved.
The huge number shocked China's leaders, who maintain strict control on the mainland.
Organisers said last year's event drew more than 200,000 people, although police said the number was much lower.
The scandal over Leung's mansion has added to worries about his integrity because he took advantage of gaffes by rival Henry Tang, including the discovery of a huge, luxurious but illegal basement extension, to win the contest.
At the time, he promised that he had no illegal structures but reporters at a local newspaper discovered over the past week that Leung's upscale home in an exclusive neighbourhood on Victoria Peak had six, including a small basement.
Leung Chun-ying (pictured above with his wife, Regina) took office in a morning ceremony [Reuters]
The scandals have stirred anger among Hong Kong residents, many of whom can only afford tiny apartments.
Yeung Sum, from the Democratic Party, told Al Jazeera while attending the annual protest that Leung is already in "big trouble."
"I think he has already lost his honeymoon, because the public are concerned about his credibility, and they are worried about his lack of integrity."
"We are worried about the legislation, or that there will be any real universal suffrage," said Yeung.
Leung is not seen as friendly to the billionaire tycoons that dominate Hong Kong and who initially backed Tang.
Trained as a land surveyor and holder of a British degree in estate management, he worked his way up to the
top of a property consultancy firm.
Some in Hong Kong also fear that Leung is an underground member of China's Communist Party because he was named to lead a committee helping to draft the Basic Law, Hong Kong's mini-constitution that would take effect on July 1, 1997, while still in his early 30s.
Leung denies that and said his volunteer activities helping to develop China's land use rights following the country's economic reform that began in 1978 earned him a good reputation in China.