Chinese President Xi Jinping arrived Thursday in Hong Kong amid tight security to attend ceremonies marking the 20th anniversary of the handover, and the inauguration of a new leader.

Xi arrived at around noon at Chek Lap Kok Airport aboard a presidential plane, on his first visit to Hong Kong since becoming president in March 2013. Xi last visited Hong Kong nine years ago as vice president.

For the three-day visit, police raised security measures to antiterrorist level, and a mobile security zone will follow Xi's entourage wherever he travels.

Hundreds of 2-meter-high water-filled plastic barriers also line the streets in the vicinity of the Hong Kong Conference and Exhibition Centre, where the inauguration ceremony will be held, and the streets surrounding hotels where the Chinese president and his delegation are staying.

In his first remarks upon arriving, Xi seemed at pains to downplay the significance of the moment, projecting a business-as-usual tone in the only part of China where Beijing's authority is attenuated.

When the former British colony was returned to Chinese rule in 1997, Hong Kong was promised a semiautonomous status under a framework allowing it to run its own affairs except for defense and diplomacy.

Fear that Beijing was reneging on that promise by pushing a restrictive electoral reform plan prompted tens of thousands of Hong Kong residents to take to the streets in late 2014, shutting to traffic the key areas of Admiralty, Causeway Bay and Mong Kok for 79 days in what became known as the Umbrella Revolution.

In his arrival remarks, Xi said China will persevere in supporting Hong Kong's development and ensure the sustainability of the "one country, two systems" framework.

Talking to the press at the airport, Xi said his visit would serve three purposes, including conveying greetings to the special administrative region, showing support for Hong Kong and planning for the future.

"I will join all parties in reviewing the achievements of Hong Kong over the past 20 years, envision the future on the back of past experience, and ensure the stable and sustained implementation of the 'one country, two systems' framework," Xi said, before leaving the airport without taking questions.

Xi later met with and complimented Hong Kong's outgoing Chief Executive Leung Chun-ying, a widely unpopular leader who is facing a corruption probe by a legislative house committee over undeclared financial dealings with a private firm.

"It was not an easy five years for you, Chief Executive Leung," Xi said before the meeting was closed to the press. "You have done a great job, endorsing the spirit of the Basic Law, especially in maintaining national sovereignty, safety and development interests (in Hong Kong)."

During his visit, Xi will preside over the inauguration of the new chief executive, Carrie Lam, and of her Cabinet.

Xi and his wife, Peng Liyuan, will also attend an official dinner hosted by Leung and a cultural performance, as well as visit a cultural development project, a People's Liberation Army barrack, a youth cadet school and a kindergarten, local media reported.