"The proposed sale will improve the ROK's capability to meet current and future threats by strengthening its Army heavy lift capability," the Defense Security Cooperation Agency said in a statement, using an abbreviation for the Republic of Korea.

"The CH-47F will allow the ROK to conduct missions in support of bilateral operational plans which include, but are not limited to, medical evacuation, search and rescue, parachute drops, and disaster relief," it added.

The State Department approved the possible sale, and the DSCA on Tuesday provided the required notification to Congress, which still needs to sign off on the transaction.