Hong Kong announced a new coronavirus policy Wednesday that would impose travel restrictions on those coming from the U.S. 

The policy would require travelers to show proof that they tested negative for COVID-19 within three days of their flight to Hong Kong. However, in many parts of the U.S., test results take much longer than that timeframe.

The policy adds the U.S. to Hong Kong’s list of high-risk places due to its large number of cases, joining countries such as India, Indonesia and South Africa with new restrictions on their travelers starting later this month.

The U.S. was also excluded from a list of countries released by the European Union earlier this month that were deemed safe to travel to based on their number of new COVID-19 cases.

The list is updated regularly, and the U.S. is still not on it, though China is now tentatively on it. 

In early July, British officials announced that those traveling from the United States would still have to undergo a mandatory 14-day quarantine and would not be among those newly exempt from the rules.

The U.S. has more coronavirus cases than any other country in the world, at over 3.9 million confirmed cases, according to data from Johns Hopkins University.