(Bloomberg) -- A Reporters Without Borders representative was refused entry to the city after arriving to monitor the trial of former media mogul Jimmy Lai, the group said.

Taipei-based Aleksandra Bielakowska was questioned and searched before being turned away on Wednesday, the international non-governmental organization said in a statement, adding it was the first time one of its representatives had been blocked from entering the financial hub.

“We have never experienced such blatant efforts by authorities to evade scrutiny of court proceedings in any country,” Rebecca Vincent, RSF’s Director of Campaigns, said in the statement. She said the denial highlighted the “dire erosion of press freedom” in the once freewheeling Chinese territory.

The city’s Immigration Department said it doesn’t comment on individual cases and handles each case in accordance with the laws and policies.

Read More: Hong Kong’s No. 1 Security Target Jimmy Lai Goes on Trial

The incident comes three weeks after Hong Kong fast-tracked into law new national security legislation that raised fears of a potential chilling effect on open discussion. A Hong Kong journalist group said a broad definition of offenses could hurt journalists’ ability to report in the semi-autonomous city.

Last month, US-funded news outlet Radio Free Asia closed its office in Hong Kong, citing concerns about the safety of its staff and reporters after the city enacted the new security law known as Article 23.

Bielakowska, an advocacy officer, visited Hong Kong in December to attend the opening of Lai’s trial for offenses under a 2020 Beijing-imposed national security law. The 76-year-old Apple Daily founder could spend the rest of his life in prison if convicted, in a case representing the culmination of President Xi Jinping’s crackdown on free speech in the former British colony.

After she arrived at the airport Wednesday, Bielakowska was stopped at the immigration office, detained for six hours and questioned throughout her detention, the group said. Bielakowska said in an interview that officers didn’t explain her detention other than citing “immigration reasons,” and didn’t mention Lai during the questioning.

She traveled with a colleague, Asia-Pacific Bureau Director Cédric Alviani, who was allowed to enter Hong Kong but returned to Taiwan later that day. Bielakowska said she could have been targeted partly because she’s more vocal and active in taking media interviews. Her colleague left due to security concerns, she said, as “we didn’t know what might happen to him when he stayed there.”

Reporters Without Borders said it wants an explanation for the episode and a guarantee its representatives can return to monitor the trial.

The Paris-based advocacy group ranked Hong Kong 140 out of 180 places in its 2023 World Press Freedom Index, declining from 18th place in the span of two decades.

Read More: Hong Kong Passes New Security Bill, Triggering Warnings Overseas

--With assistance from Sarah Zheng, Rebecca Choong Wilkins, Alan Wong and Richard Frost.

(Updates with comments from government and Bielakowska)

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