Delivery of Taiwan’s first new F-16 fighters built by Lockheed Martin has been delayed by problems deeper than the COVID-related supply chain issues cited previously, according to the U.S. Air Force.

"Complex developmental challenges” have been encountered, and the U.S. government, Taiwan and Lockheed "are actively working to mitigate these delays,” according to an Air Force statement flagging the previously undisclosed technical issue without elaboration. "We are committed to do everything we can to find solutions to deliver these aircraft, fully capable, to our partners as soon as possible.”

The F-16 has been in service since 1979, and Taiwan already has older models. The latest "Block 70” fighters are equipped with a "fire control radar” made by Northrop Grumman that’s designed to allow the firing of precision-guided munitions from greater distances. The first Block 70 flew in January, and Bahrain, another Block 70 customer, has taken delivery of its first jet.