Tens of thousands of pro-democracy marchers have marched through the streets of Hong Kong as the former British colony marked 15 years since the return to Chinese rule.
The rally for human rights takes place annually, but has been bolstered this year by anger towards Beijing.
Police had to shield the president from demonstrators, and officers used pepper spray to disperse crowds who were demanding an investigation into the death in China of a Tiananmen activist, Li Wangyang, last month.
His visit comes as public confidence in the Beijing government has fallen to a new low.
People are unhappy with record property prices, an increasing wealth gap, a lack of democracy and a string of political scandals.
China's leaders in Beijing have resisted public pressure for full democracy in the city.