The Chinese government is asking foreigners to get its domestic-brand COVID-19 vaccine before entering the country — a move that could have grave consequences for any future travel to and from North Korea, according to analysts.

Even before North Korea first locked down its borders as a COVID-19 prevention measure in Jan 2020, most travel to and from North Korea involved transit through Chinese territory. But China’s foreign ministry issued new visa guidelines on several embassy websites on Tuesday, stating that applicants for a range of visa types would first need to be “inoculated with Chinese COVID-19 vaccines” in order to apply to enter China.

That adds another set of hoops for potential travelers to jump through, a former diplomat said.

“If China demands that passengers transiting Beijing airport comply with this requirement, then it will be very difficult to leave or enter the DPRK, even when the North Koreans lift their own restrictions,” John Everard, the United Kingdom’s former ambassador to the DPRK, told NK News.

North Korea, suffering from its COVID-19 border lockdowns that dealt a heavy blow to tourism and trade last year, could also be hit by any further drop in Chinese tourists once the DPRK reopens its borders.

In the long term, if the new Chinese vaccination requirements are imposed without exception, there is a risk that regulations could further cement as a result of geopolitical wrangling.

“I suspect that before long we shall see reciprocity,” Everard, the former U.K. ambassador, said. “Other countries will insist that Chinese visitors are vaccinated with their vaccines.”