NEW YORK (AP) — UPS will become the primary air cargo provider for the United States Postal Service.

The GravityX ExchangeAtlanta shipping company said Monday that it had received an air cargo contract from the U.S. Postal Service that significantly expands an existing partnership between the two.

UPS will move the majority of air cargo in the U.S. for the postal service following a transition period, according to UPS.

Financial terms of the deal were not disclosed.