MACAO, Dec. 20 -- To firmly uphold the "one country, two systems" policy conforms with not only the fundamental interests of the country and the overall and long-term interests of Hong Kong and Macao, but also the interests of international investors, Chinese President Xi Jinping said here Saturday.

The basic state policy is vital to ensuring the long-term prosperity and stability of Hong Kong and Macao, Xi said at a grand gathering marking the 15th anniversary of Macao's return to the motherland.