A fleet of F-35 stealth fighters arrived in South Korea from the U.S. on Tuesday, according to the U.S. Army, a move one expert said signals to North Korea that U.S.-ROK combined training has returned to “normal levels.”

The aircraft are scheduled to carry out a 10-day training mission over the Korean Peninsula and surrounding waters, according to U.S. Forces Korea (USFK), and will fly with several other U.S. and South Korean aircraft. 

“The familiarization and routine training flights will enhance the interoperability of the two Air Forces to perform and operate on and around the Korean Peninsula,” U.S. Forces