Troubled carrier Cathay Pacific Airways Ltd. received another blow as Hong Kong unveiled a policy that threatens to eliminate nearly all travel from the U.S.

All passengers in the U.S. must prove they tested negative for Covid-19 within three days of their flight to Hong Kong, the city’s government announced Wednesday. The policy adds the U.S. to a list of “high risk places” that includes India, Indonesia and South Africa.

However, in many parts of the U.S., getting results from a Covid-19 test within 72 hours is nearly impossible. Because of skyrocketing demand, hospitals are still finding themselves short on supplies and even major labs, like Quest Diagnostics Inc., are so bogged down that the turnaround times can exceed a week.

Before the pandemic, Cathay had direct flights to multiple U.S. cities, including several a day from New York. That lineup has shrunk to just a few flights a week. The carrier closed its cabin crew bases in the U.S. in April because of the impact the virus had on global travel.

Cathay, which warned last week of a HK$9.9 billion ($1.3 billion) first-half loss, has turned to the government for support in a HK$39 billion rescue plan. Its shares have fallen 43% so far this year.