SHANGHAI (Reuters) - Leading members of China's parliament said on Saturday two Hong Kong lawmakers-elect who called for the city's independence from China had damaged the territory's rule of law and posed a grave threat to China's sovereignty and security.

The comments, carried on state TV, come ahead of what is expected to effectively be a ruling by Beijing on the fate of Yau Wai-ching, 25, and Baggio Leung, 30, who set off fierce debate when they pledged allegiance to the "Hong Kong nation" and displayed a "Hong Kong is not China" banner during a swearing-in ceremony for the city's legislative council in October.

Britain returned Hong Kong to Chinese control in 1997 under a "one country, two systems" formula that gave the territory wide-ranging autonomy, including judicial freedom guided by a mini-constitution called the Basic Law.

China's parliament, the National People's Congress, has a right to weigh in on the Basic Law, and on Saturday senior members of the NPC discussed a draft interpretation of the Law's article that requires Legislative Council members and other officials to pledge loyalty to Hong Kong as a part of China when taking office.

The Chinese lawmakers agreed that the legislators-elect from Hong Kong had "humiliated the nation and the people", according to China Central Television (CCTV).

They "brazenly challenged the Basic Law, impeded the normal operations of Hong Kong Special Administrative Region political organs, damaged Hong Kong's rule of law, assaulted the baseline principles of 'one country, two systems', and created a serious threat to the nation's sovereignty and security", it said.

"If this kind of situation continues it will harm the immediate interests of the people of the Hong Kong Special Administrative Region and the interests of national development. The central government cannot sit by indifferently," they were quoted as saying.

As such, an NPC interpretation was "very timely and extremely necessary".

The oath-taking incident made waves in the former colony, where the topic of independence from China was once regarded as taboo but has come to the fore since months of pro-democracy protests in 2014 failed to secure any concessions from Beijing.

The parliamentary meeting in Beijing ends on Monday, the state news agency Xinhua said.

Earlier in the day, the Communist Party's top newspaper, the People's Daily, ran an editorial that said anyone "who splits the nation or promotes 'Hong Kong independence' is ... unqualified to stand for election or hold public office provided for in the Basic Law".

The NPC Standing Committee has interpreted the Basic Law four times since 1997, including once when neither the city government nor its courts requested it.

After the abortive swearing-in of Yau and Leung, Hong Kong's chief executive filed a lawsuit seeking an injunction to prevent another ceremony for them taking place.

Hong Kong's High Court struck down that request but approved a judicial review of the pair's membership of the legislature.

The Hong Kong Bar Association has said an intervention by Beijing now, as a local court was hearing the case, would deal a severe blow to the city's judicial independence and undermine international confidence in Hong Kong's autonomy.

(Reporting by John Ruwitch; Additional reporting by Venus Wu in HONG KONG; Editing by Catherine Evans and Stephen Powell)