MANILA, Philippines — Philippines Airlines said Thursday it is cooperating with the government in resolving what authorities said are 7.28 billion pesos ($143 million) in unpaid navigational fees and other charges.

Philippine Airlines said the allegedly unpaid charges involve “complex legal issues” which it has been trying to thresh out with the Civil Aviation Authority of the Philippines for years.

President Rodrigo Duterte has warned PAL to settle its arrears in 10 days or risk the closure of its airport terminal.

“I said ‘you solve the problem yourself. I will give you 10 days,'” Duterte said in a speech. “‘If you don’t pay, I will destroy that and there will be no more airport.'”

The Department of Transportation said letters were sent to PAL as early as August 2016 demanding full payment of all unpaid charges.

PAL suggested the possibility of paying its arrears over seven years, but the request was denied. The final demand for full payment has been sent to the airline in preparation for legal action, according to the department.

“PAL has fully cooperated and will continue to cooperate with any and all agencies to resolve this concern,” the airline said, adding that it earlier expressed its willingness to settle amicably with the government.