SEOUL — A Chinese man who washed up on South Korea's west coast last week after crossing the Yellow Sea on a water scooter, is thought to be a political dissident who was once imprisoned in China, a South Korean human rights activist said Wednesday.

Kwon Pyong, a 35-year-old ethnic Korean whose name in Mandarin is Quan Ping, arrived in the port city of Incheon last week, Lee Daeseon, a Korea-based human rights activist, said in a telephone interview. Incheon, an hour's drive west of the capital Seoul, is the home of the country's main airport.

Lee said Kwon had traveled more than 300 kilometers, or about 200 miles, on the personal watercraft from China's Shandong province to reach South Korea, where some of his relatives live. Lee, who has known Kwon since 2019, said he confirmed the man's identity after being allowed a visit Tuesday to a coast guard facility where Kwon was being held. A close relative in South Korea also confirmed that the individual is Kwon, according to Lee, who said he had spoken to that relative.

Kwon is seeking political asylum outside China, preferably in the United States, Britain or Canada, Lee said. "Kwon is in good health and good spirits," he said. Kwon previously studied as a college student in Iowa, Lee said.

The Korean coast guard said in a news release Sunday that an individual on a 1,800-cc red water scooter — carrying more than 200 liters, or more than 50 gallons, of fuel — had beached on Incheon's wetlands and was detained for crossing the border illegally. It said the person had visited Korea previously but did not disclose the individual's name and refused to comment further, citing privacy concerns.

The coast guard's details of how the man was found suggested he had prepared for the trip thoroughly: He was wearing a life jacket and a helmet and carrying binoculars and a compass. He had dumped empty fuel canisters into the sea after refueling along the way.

In 2017, Kwon was jailed for 18 months in China for "inciting subversion of state power" after he posted speeches, images and videos on social media critical of the Chinese government. In one photo, Kwon wore a white T-shirt that likened China's top leader, Xi Jinping, to Hitler. A Chinese court said Kwon had insulted the "state authority and the socialist system," according to Front Line Defenders, an advocacy group that has followed his case.

Since being released from prison, Kwon has been subject to an exit ban stopping him from departing China legally, Lee said. He tried to leave China and enter Korea by filing a political asylum application in 2019, but the process was eventually canceled because of the travel ban. Under Xi, China is increasingly using exit bans to keep critics of the regime — citizens and foreigners alike — in the country, where they can be more easily surveilled and silenced.

The Chinese Embassy in Seoul refused to comment, saying it has no relevant information about the case.

After returning from Iowa, Kwon worked for a family business in his hometown of Yanbian, a trade hub on the China-North Korea border. On social media platforms that are now banned in China, he posted criticism of the government's censorship and political controls and support for dissidents and protests, his former attorneys said online and to the media in 2019. All of his Facebook and Twitter posts have since been deleted.