Cracks were found in two F-15 fighter jets based in Japan during checks following the crash of an F-15C in the United States last month, according to the U.S. military.

The cracks were close to the canopies on the two fighters, which were among 30 F-15s inspected at the Kadena Air Base in Okinawa Prefecture, the U.S. Air Force said in a statement Thursday.

The cracks were found during checks after the U.S. Air Force issued a second flight suspension order for the fighters worldwide following an F-15C crash in Missouri last month in which the pilot was injured. The first suspension was lifted on Nov. 21 but planes were grounded for a second time later that month after additional defects turned up.

The Air Self-Defense Force said inspections of its 200 or so F-15s after the crash had found no problems.