TAIPEI--A Hong Kong bookseller who fled to Taiwan amid fears of Chinese persecution was attacked on Tuesday by a man who threw red paint at him, just days before he was set to open a new bookshop in Taipei.

Lam Wing-kee, who sought refuge in Taiwan last year after he was detained by Chinese agents in 2015 while working at a bookshop in Hong Kong that sold books critical of the Chinese leadership, had red paint poured over him in a Taipei cafe.

The attack came days after Hong Kong police launched a surprise crackdown on pro-democracy activists.

A growing number of protesters have been fleeing Chinese-ruled Hong Kong to democratic Taiwan, which has repeatedly rejected Beijing’s proposals to rule the island with the “one country, two systems” model it uses for Hong Kong.

Taiwan has also voiced its strong support for the Hong Kong protesters.

“I was attacked with red paint in the cafe,” Lam told Reuters by telephone while assisting the police with their investigation.

“Some people don’t want me to open the bookshop in Taiwan,” Lam said, describing the attack as a threat by supporters of Beijing.

Police are hunting for the assailant, reviewing security camera footage from the scene, the official Central News Agency reported.

Lam’s incarceration was part of a coordinated operation by China’s security apparatus that led to five booksellers disappearing from locations in China, Hong Kong and Thailand in late 2015, and later showing up in Chinese detention where they were forced to make confessions on public television.

The case generated huge controversy, and undermined public confidence in China’s commitment to preserving Hong Kong’s freedoms.

Before its closure in Hong Kong after the booksellers’ arrests, Lam’s “Causeway Bay Books” had become a symbol of resistance to perceived Chinese encroachments on Hong Kong’s liberties. Lam’s new shop in Taipei will bear the same name.

Taiwan’s Mainland Affairs Council, which oversees the island’s policy towards China, condemned the attack and said anyone who sought to challenge the law would be “severely punished.”

Lam last year decided to move to Taiwan months before a controversial law was expected to be passed in Hong Kong that would allow individuals to be sent to China for trial.

The incident on Tuesday was the latest attack on Hong Kong pro-democracy activists in Taiwan. Activists told Reuters last year they were coming under increased surveillance and harassment from pro-China media outlets and unofficial “operatives.”

Hong Kong singer and activist Denise Ho was attacked in September by a masked man who threw red paint at her at a pro-Hong Kong democracy rally in Taipei.

In July 2018, two Taiwanese were convicted of assaulting Hong Kong activists meeting with independence advocates in Taipei.