President Donald Trump’s administration said on Wednesday it will bar Chinese passenger carriers from flying to the United States starting on June 16 as it pressures Beijing to allow U.S. air carriers to resume flights.

The move, announced by the U.S. Department of Transportation, penalizes China after Beijing failed to comply with an existing agreement on flights between the world’s two largest economies. Relations between the two countries have also soured in recent months amid escalating tensions surrounding the coronavirus pandemic.

The order applies to Air China, China Eastern Airlines Corp, China Southern Airlines Co and Hainan Airlines Holding Co.

Delta Air Lines and United Airlines have asked to resume flights to China this month, even as Chinese carriers have continued U.S. flights during the pandemic. Delta said in a statement on Wednesday that “we support and appreciate the U.S. government’s actions to enforce our rights and ensure fairness.” United did not immediately comment.

China “remains unable” to say when it will revise its rules “to allow U.S. carriers to reinstate scheduled passenger flights,” the Transportation Department said in a formal notice made public on Wednesday.

The Chinese embassy in Washington did not immediately respond to a request for comment.

The Trump administration on May 22 accused China’s government of making it impossible for U.S. airlines to resume service to China and ordered four Chinese carriers to file flight schedules with the U.S. government.

The Chinese carriers are flying no more than one scheduled flight a week to the United States but also have flown a significant number of additional charter flights, often to help Chinese students return home.

The Trump administration is also cracking down on Chinese passenger airline charter flights and will warn carriers not to expect approvals. Administration officials have suggested charter flights have been used to circumvent Chinese government limits on flights.

On Jan. 31, the U.S. government barred from entry most non-U.S. citizens who had been in China within the previous 14 days due to the coronavirus crisis but did not impose any restrictions on Chinese flights. Major U.S. carriers voluntarily decided to halt all passenger flights to China in February.

Delta and United are flying cargo flights to China. Delta had requested approval for a daily flight to Shanghai Pudong airport from Detroit and Seattle, while United had asked to fly daily to Shanghai Pudong from San Francisco and Newark airport in New Jersey and between San Francisco and Beijing.

China’s air authority in late March said Chinese airlines could maintain just one weekly passenger flight on one route to any given country and that carriers could fly no more than the number of flights they were flying on March 12, according to the U.S. order.

But because U.S. passenger airlines had stopped all flights by March 12, China “effectively precludes U.S. carriers from reinstating scheduled passenger flights to China,” the Transportation Department said.