Communist Party members should study contemporary capitalism but must never deviate from Marxism, Chinese President Xi Jinping has said, offering a clear signal there will be no weakening of party control weeks ahead of a key party congress.

The party brooks no challenge to its rule, and Xi has overseen a sweeping crackdown on civil society since assuming power almost five years ago, tightening the party's grip over the internet, media and security infrastructure, and locking up rights lawyers and dissidents.

Speaking at a study session of the Politburo, one of the party's elite ruling bodies, Xi said that while times are changing and society is developing, the basic tenets of Marxism remain true, the state news agency Xinhua said late Friday.