BEIJING - Xi Jinping said Wednesday the policy of "one country, two systems" has proved to be the best institutional guarantee for the long-term prosperity and stability of Hong Kong and Macao after their return.

The policy is the best solution to the questions of Hong Kong and Macao, Xi said while delivering a report at the opening session of the 19th national congress of the Communist Party of China.

The governments and chief executives of both regions will be supported to advance democracy with well-ordered steps, maintain law and order, and fulfill the constitutional responsibility of safeguarding China's sovereignty, security, and development interests, he said.

"We will continue to support Hong Kong and Macao in integrating their own development into the overall development of the country," he said, adding that priority will be given to the development of the Guangdong-Hong Kong-Macao Greater Bay Area; cooperation between Guangdong, Hong Kong, and Macao; and regional cooperation in the pan-Pearl River Delta.

Policies will be improved to make it more convenient for the people from Hong Kong and Macao to pursue career development on the mainland, he said.

Xi stressed that patriots should play "the principal role" as the Hong Kong people govern Hong Kong and the Macao people govern Macao.