The government of Pakistan is in the process of securing a deal with the U.S. government for the delivery of new F-16 fighter jets.

The deal was discussed by Pakistan Air Force Air Chief Marshal Sohail Aman, whoconfirmed to local media outlets at the Pakistan Aeronautical Complex that officials are in talks. The announcement came during the rollout ceremony of the 16th JF-17 Thunder aircraft.

“We are in talks with U.S. defence officials to get some latest F-16s but the deal may take some time,” Aman said.

Aman did not disclose the number of aircraft to be procured. Pakistan’s Air Force already includes over 70 F-16s, in addition to dozens of Chinese and French attack aircraft. The United States has been selling the fighters to the country since the two governments inked a deal in the 1980s.

While U.S. lawmakers have been critical of arms sales to Pakistan, Defense News reports there is an interest in maintaining the relationship to keep the F-16 production line open. With the U.S. Department of Defense moving forward with its next-generation F-35 Lightning II program, which is meant to replace the F-16 fleet, the F-16 program is relying on exports and no longer enjoys domestic demand.

Pakistan’s potential procurement of F-16s is part of its effort to modernize its fleet, which includes aging models such as the Mirage III/5. Pakistan hopes to replace its older generation jets by 2020.