Protesters hold up pictures of Hong Kong Chief Executive-elect Leung Chun-ying during a protest against Leung in Hong Kong…Sunday

AFP

Defiant protestors targeted China's President Hu Jintao in Hong Kong on Sunday as the former British colony swore in a new leader and marked the 15th anniversary of its return to Chinese rule.

"I vow to defend the Hong Kong... Basic Law," said new Chief Executive Leung Chun-ying, a millionaire property consultant seen as close to China's communist rulers, as he read out the oath before shaking hands with Hu, reports AFP.

The Basic Law is Hong Kong's mini-constitution, which guarantees the former British colony civil liberties unheard of on the mainland under the "one country, two systems" model set up when it returned to China in 1997.

But Hu's visit and the inauguration came as discontent towards Beijing surges to a new post-handover high, and security has been stifling for the events, with hundreds of police and giant barricades deployed.

As the president began his speech to around 2,300 guests in a harbour front convention hall, a protestor repeatedly shouted "End one-party rule".

The man also referred to the crushing of democracy protests on Tiananmen Square in Beijing on June 4, 1989, and was rapidly surrounded and taken away as the audience drowned him out with extended applause for Hu's opening remarks.

The Chinese president said that Beijing's support for "one country, two systems" and the right of the people of Hong Kong to rule the territory was "unwavering".

"We will follow the Basic Law... to continue to advance democratic development in Hong Kong," said Hu, who will step down as part of a once-in-a-decade leadership transition in Beijing starting later this year.

But Hong Kong does not yet choose its leader by universal suffrage, and Leung was elected as chief executive in March by a special committee stacked with pro-Beijing business elites.

Protestors have been demanding greater democracy and railing against Beijing's meddling in local affairs.

Ahead of the inauguration, a group of demonstrators burned Leung's portrait, shouting: "Battle the Communist Party! We will battle to the end!"

Elsewhere, marchers held aloft a mock red coffin emblazoned in Chinese: "The Liaison Office (Beijing's representative) governs Hong Kong."

Hu -- who said Friday he hoped to "walk more" and "understand" Hong Kongers' "life and expectations" -- had been expected to attend an earlier flag-raising ceremony on the city's iconic waterfront.

But his absence was noticeable as three helicopters trailed the Chinese and Hong Kong flags in a flypast over the harbour, the national emblem in front and at least four times larger, and a flotilla of boats steamed past.

The Chinese leader flew out shortly before noon, ahead of an annual rights rally expected to see tens of thousands of people take to the streets.

On Saturday police used pepper spray to push back a few dozen demonstrators who tried to get past barricades more than two metres (6.5 feet) high near Hu's hotel.