A wave of Chinese citizens "desperate" to flee an oppressive regime and cross illegally into the U.S. is a "perfect opportunity" for the communist party to smuggle in its agents, a China expert said.

"There is deep pessimism in Chinese society and that is driving people to leave the country," Gordon Chang, who has authored books about China, told Fox News. "They are desperate."

Border Patrol apprehensions of Chinese nationals crossing illegally into the U.S. rose more than 800% compared to the same period last fiscal year when including January — the numbers for which have not yet been released, a senior Customs and Border Protection source told Fox News.

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Chang said nearly three years of China’s "zero COVID" strategy, which included strict lockdowns, mass testing, quarantines and contact tracing, was the initial driving factor pushing Chinese citizens to find refuge elsewhere. 

"They just found it unbearable," he said. 

Additionally, a contracting Chinese economy and plummeting property prices are causing people to leave, according to Chang. 

"There is just a sense of unease in the country," he told Fox News. "People make the case that the country will recover somewhat, but the Chinese regime is not solving the fundamental causes of problems." 

As a result, "the flow of refugees from China will not diminish," Chang said. 

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There have been 1,862 Border Patrol encounters with Chinese nationals between October, when the fiscal year began, and the end of December, compared to 229 during the same period last year, according to CBP data. In December, there were 931 Chinese nationals encountered, compared to 64 in December 2021.

Amid the spike of Chinese crossing the U.S. border, the Department of Homeland Security is monitoring closely for potential Chinese spies and other national security threats, a source previously told Fox News. 

migrants cross southern border

The southern border has been consistently overwhelmed with the migrant surge. There were more than 215,000 migrant encounters in December. (John Moore/Getty Images)

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"Almost all the Chinese coming up through the Darién gap to the U.S. southern border are people who do not want to live in China," Chang said. "But we have to assume that the Chinese regime is taking advantage of the situation by smuggling in their agents." 

While America continues to grapple with a historic migrant crisis, with more than 251,000 migrant encounters in December, Chang said it is "a perfect opportunity for the Chinese security services to put their people in the U.S."

"Our southern border is undefended and there are bad actors coming in," he added. "We need to get control of the situation."

Fox News' Bill Melugin contributed to this report