Boeing is planning to suspend production of its grounded 737 Max planes next month, the company announced. The drastic measure comes after the Federal Aviation Administration said its review of the planes would continue into next year.

“Throughout the grounding of the 737 MAX, Boeing has continued to build new airplanes and there are now approximately 400 airplanes in storage,” the company said in a statement.

“We have previously stated that we would continually evaluate our production plans should the MAX grounding continue longer than we expected. As a result of this ongoing evaluation, we have decided to prioritize the delivery of stored aircraft and temporarily suspend production on the 737 program beginning next month.”

It is not clear yet how long Boeing will keep its the suspension of the 737 Max production line. U.S. airlines have taken the planes out of their schedules until at least March. American last week said it doesn’t expect to fly the planes before April. Southwest just announced that it will not fly the plane at least until Easter is Sunday, April 12.

Boeing’s 737 MAX aircrafts were grounded globally in March after two crashes that killed hundreds of passengers. The fatal crashes were blamed on problems with the aircraft’s software and US authorities are investigating. The incident has so far cost Boeing at least $9.2bn. But according to J.P. Morgan, Boeing will still burn more than $1 billion a month even after halting 737 Max production.