A Chinese dissident who has been living in a Taiwanese airport since Friday has pleaded for the United States or Canada to grant him asylum after he fled Thailand saying he feared being deported back to China.

Chen Siming, known for his annual commemorations of the 1989 Tiananmen Square massacre, which is heavily censored and remains a major political taboo in China, told CNN he fled China in July after coming under increasing pressure and scrutiny from authorities.

He has been commemorating the anniversary of the massacre -- which saw troops and tanks forcibly clear a Beijing square full of students and pro-democracy protesters -- since 2017, both through street demonstrations and on social media.

Those activities had previously resulted in Chen being penalized or placed in administrative detention, but he said Beijing's grip has tightened significantly in the past few years.

Dissidents and civil society activists have experienced a widening crackdown under leader Xi Jinping, China's most assertive leader in a generation.

Chen described receiving daily calls from the police, who would come to his house if he didn't pick up; other times, police would ask him to report to the station, seemingly arbitrarily.

Chen told CNN he "felt sad, angry and afraid" after receiving such a call on July 21, when police told him to undergo a psychiatric evaluation.

After returning home from the police station, he packed his clothes and fled, traveling across China until he made it to the southern border with Laos, a common but risky land route for those trying to flee.

When evening fell, he crossed the border into the Laos mountains, he told CNN -- and by early August, he'd crossed the Mekong River and entered Thailand.

While in Thailand, Chen said, he registered as a refugee with the United Nations High Commissioner for Refugees, describing an expedited process -- but he still didn't feel safe, fearing that his refugee status wouldn't protect him from being detained by Thai police or immigration authorities.

The Southeast Asian kingdom does not recognize the concept of asylum and instead outsources refugee claims to the United Nations, which seeks to settle successful claimants in third countries. Many people spend years in Thailand before being resettled.

Many Chinese dissidents do not feel safe in Thailand given the government's often friendly links with Beijing, and in the past dissidents based there have turned up in Chinese custody.

Eventually Chen decided to flee Thailand, too -- and landed in Taipei on Friday, on a layover to Guangzhou. Upon arrival at Taoyuan International Airport, he posted a video to X, the platform formerly known as Twitter, saying: "To avoid the political oppression of the Chinese Communist Party, I have now come to Taiwan."

"I hope to receive political asylum from the US or Canada. I ask friends to call on the Taiwanese government to not send me back to China," he said in the video, adding in a caption: "I am forced to be illegally stranded here."

Dissidents fleeing abroad

Taiwan is a self-governing democratic island, home to 24 million people, which Beijing's ruling Communist Party claims as its territory despite never having controlled it.

In recent years it has also increasingly been seen as a safe haven for dissidents fleeing China, including pro-democracy protesters and leaders from Hong Kong as Beijing cracks down on the city.

However Taiwan also does not have any local laws recognizing the concept of asylum and the UN's refugee agency does not operate there.

Soon after posting his video, Chen was taken for questioning by Taiwan's immigration authorities and the Mainland Affairs Council, he told CNN. He is still at the airport.

Taiwan's Mainland Affairs Council told CNN on Monday: "With regard to the matter of Chinese dissident Chen Siming being stranded at the Taoyuan International Airport, the government is currently working on it, and is not able to share relevant details."

In 2019, two Chinese dissidents spent months living at Taoyuan before their cases were eventually resettled.

UNHCR declined to comment on Chen's case. CNN has reached out to China's Taiwan Affairs Office for comment.

As Chen waits for his case to be processed, he is hoping for eventual asylum in the West, either in Canada or the United States.

"Given the current political climate in China, there is no space for me to operate there," he told CNN. "I hope the US government will stand with the Chinese people, and help bring an end to the authoritarian rule of the Chinese Communist Party, so that China has democracy."

His dramatic journey follows other cases in recent years that have highlighted the dangers to Chinese dissidents seeking refuge in Southeast Asia.

For decades, critics of the Chinese Communist Party fled to Thailand -- but that, too, has become riskier in recent years.

In 2015, two members of a small exiled Chinese opposition political party -- Jiang Yefei and Dong Guangping -- were arrested by Thai police. Several weeks later, despite protests from the United Nations High Commissioner for Refugees, the two men were extradited to China and imprisoned.

After Dong's extradition, his wife and daughter fled Thailand for Canada.

More recently in August this year, prominent lawyer Lu Siwei was arrested in Laos while traveling to the United States, facing threat of deportation back to China. Laos lies across China's southwestern border and has long been a common, albeit risky, exit point for Chinese dissidents trying to leave the country.

Lu was known for navigating China's opaque criminal system, taking on sensitive cases for years -- until his license was revoked by authorities in 2021 for representing one of the 12 activists who were intercepted by Chinese coastguards at sea on their way to Taiwan while trying to flee Hong Kong.

The news of his arrest also prompted dozens of human rights groups to sign a petition calling on Laos authorities to release Lu and to halt deportation processes, citing "the high likelihood of torture and other ill-treatment" should Lu return to China.

Chen, too, has received support from activist communities since his arrival in Taiwan.

Wang Dan, a student leader during the 1989 Tiananmen Square protests who has since lived in exile, tweeted on Saturday that the world was "very concerned" about Chen's request for asylum. He added that he had joined efforts to help Chen, and believes there will be a good outcome.