China will stay true to the letter and spirit of the principle of "One Country, Two Systems," under which the people of Hong Kong administer Hong Kong and the people of Macao administer Macao with a high degree of autonomy, Chinese President Xi Jinping said on Thursday.

President Xi, also general secretary of the Communist Party of China (CPC) Central Committee and chairman of the Central Military Commission, made the remarks during a speech at the ceremony marking the centenary of the CPC in Beijing.

He said the CPC will ensure that the central government exercises overall jurisdiction over Hong Kong and Macao, and implements the legal systems and enforcement mechanisms for the two special administrative regions to safeguard national security.

"China's sovereignty and national interests must be safeguarded," Xi said. "Hong Kong and Macao's long-term prosperity and stability must be protected."