"I can understand that the central authorities are very concerned".
Xia also laid out the criteria for what makes a "real patriot", including love for the People's Republic of China, its constitution and the Communist Party.
Lam said in in a news conference on Monday that reforms would not be created to limit the influence of pro-democracy politicians but that no one in government should engage in unpatriotic activities, such as colluding with foreign powers to subvert China's central government.
The "patriotism" requirement for the city's fiercely independent judiciary would be of particular concern for many in Hong Kong, as its common law-based system has been key to establish the city as a global financial hub.
"The CCP is the creator and leader of the "one country, two systems" model".
According to a discussion paper prepared for Monday's meeting by the European External Action Service, the EU should explore options such as asking all EU member countries to terminate their extradition treaties with China, and planning high-level joint visits to Hong Kong.
Hong Kong's current chief executive, Carrie Lam - who became immensely unpopular during the 2019 protests and the brutal police crackdown against demonstrators - applauded Beijing's decree that only "patriots" would be allowed to participate in city government, not "troublemakers".
She said political unrest in the former British colony, including massive protests in 2019, had forced Beijing to ensure the city is governed by patriotic officials. Lam's five-year term will conclude early next year.
"This need to change the electoral system and arrangements in Hong Kong is for one single objective, that is to make sure that whoever is governing Hong Kong is patriotic", she said.
The Legislative Council will debate the Bill on March 17.
Any changes could further limit who could run in a postponed legislative election and may lead to the disqualification of most lower-level district councillors - the majority of them being pro-democracy politicians, sources have told Reuters.
Patriots would also resolutely oppose foreign interference in Hong Kong, he said.
Andrew Leung, the pro-Beijing president of Hong Kong's legislature, told reporters on Monday that Xia was "outlining the red lines for people holding high offices in Hong Kong".