The United States said Wednesday it will prohibit Air China planes from entering the country beginning on June 16 as part of an effort to pressure Beijing to allow American air carriers to resume flights to China.

The U.S. Department of Transportation said the move came after China did not conform to an existing deal between the two countries that addresses international travel.

The agency said China rejected requests from United Airlines and Delta Airlines to resume flights to China on June 1.

China "remains unable" to say when it will revise its rules "to allow U.S. carriers to reinstate scheduled passenger flights," the agency said.

The requests from the U.S. airliners came even as Chinese carriers have continued flights to the U.S. during the coronavirus pandemic, further escalating tensions between the world's two largest economies.

The U.S. is also restricting Chinese passenger airline charter flights and will warn carriers not to expect approvals.

Because of the pandemic, the U.S. barred most non-U.S. citizens who had been in China within the previous 14 days from entering the U.S. but did not impose restrictions on Chinese flights. Most large U.S. airlines voluntarily stopped all passenger flights to China in February.

Delta Airlines said Wednesday "we support and appreciate the U.S. government's actions to enforce our rights and ensure fairness."

United Airlines did not immediately comment, nor did the Chinese Embassy in Washington.

An earlier version of this story mistakenly featured a photo of a Taiwan China Airlines plane, which is distinct from China's Air China. VOA regrets the error.