This article was originally published Dec. 2, 2015.

WASHINGTON — Lockheed Martin has been awarded a $914 million contract to upgrade F-16s for Singapore's government, the Pentagon announced on Tuesday.

The fighter jet upgrades, which are the result of a sole-source acquisition, will take place at Fort Worth, Texas, and should be finished by June 30, 2023. The number of aircraft to be upgraded was not immediately known, but the Defense Department told Congress in 2014 that it had approved selling upgrades for 60 of Singapore's F-16s, according to Reuters.