The White House is calling on China to "immediately release" Cardinal Joseph Zen and others who were arrested by Hong Kong authorities Wednesday, White House deputy press secretary Karine Jean-Pierre told reporters during a press briefing.

Why it matters: Zen and the other individuals arrested were trustees of the 612 Humanitarian Relief Fund, a now-defunct fund that helped pay legal and medical fees for demonstrators arrested in the city's pro-democracy protests in 2019, AP reported.

• Their arrests come after Hong Kong police began investigating the fund last year for alleged violations of China's national security law, which has been used to crack down on Hong Kong's protesters and free press.

The big picture: Zen is among the most senior Catholic clerics in Asia and a longtime advocate for democratic causes in Hong Kong, as well as a fierce critic of President Xi Jinping's authoritarianism, per Reuters.

• The others were lawyer Margaret Ng, singer and activist Denise Ho and scholar Hui Po-keung, per Reuters.
• “Today’s arrests signal beyond a doubt that Beijing intends to intensify its crackdown on basic rights and freedoms in Hong Kong,” Benedict Rogers, chief executive of human rights group Hong Kong Watch, said in a statement.

What they're saying: “We call on PRC and Hong Kong authorities to cease targeting Hong Kong’s advocates and to immediately release those who have been unjustly detained and charged, like the Cardinal Joseph Zen and others arrested today,” Jean-Pierre said, referring to the People’s Republic of China.

• Freedom of expression is "critical to prosperous and secure societies," she added.
• “The Holy See has learned with concern the news of Cardinal Zen’s arrest and is following the development of the situation with extreme attention," Vatican spokesperson Matteo Bruni said in a press release.