Top generals from South Korea, the United States and Japan have agreed to expand the scale of the three sides' first-ever "Freedom Edge" combined multi-domain exercise held earlier this year.

The agreement was reached on Thursday between Seoul's Joint Chiefs of Staff(JCS) Chairman Adm. Kim Myung-soo and his American and Japanese counterparts, Gen. Charles Q. Brown Jr. and Gen. Yoshihide Yoshida, respectively, during a trilateral meeting in Tokyo.

The top generals said the Freedom Edge training, aimed at bolstering the three-way interoperability, will expand, and the three sides plan to develop a shared regional vision for peace, stability and deterrence through cooperation.

The inaugural drills were held in international waters south of Jeju Island late last month, with various vessels and aircrafts from the three sides being mobilized for training in maritime missile defense, air defense warfare, submarine defense, search and rescue, and cyber defense.

The exercise was held as a follow-up to an agreement between the leaders of the three countries last August at Camp David to hold a regular combined training covering multiple domains, amid growing nuclear and missile threats from North Korea.