Three top US military commanders plan to issue a strong warning message to North Korea in a rare joint press availability here later Tuesday, officials said.

Pacific Command chief Adm. Harry Harris, Strategic Command head Gen. John Hyten and Missile Defense Agency Director Lt. Gen. Samuel Greaves are scheduled to hold a press conference at a local US Forces Korea base.

It's quite unusual for the US commanding generals serving abroad to gather in South Korea and release public statements together.

It apparently reflects Washington's alertness against North Korea's rapid development of nuclear bombs and missiles.

In July, the North successfully test-launched two intercontinental ballistic missiles.

The US intelligence community also believes the secretive communist nation has made significant progress in miniaturizing nuclear warheads.

The US commanders are expected to stressed that a military option will be on the table as the last means to use in case of an eventual failure in efforts to resolve the North Korea issue via diplomacy, a defense source said.

They will also likely warn the Kim Jong-un regime not to miscalculate the allies' defense capabilities.

USFK chief Gen. Vincent K Brooks will be present at the press conference.

The commanders will reportedly make a tour of the new USFK base for the THAAD missile defense system in Seongju, North Gyeongsang Province, after inspecting the Ulchi Freedom Guardian combined exercise under way in Korea.

Their simultaneous trips here are also intended for introductory meetings with South Korea's new military leaders, including Defense Minister Song Young-moo and Gen. Jeong Kyeong-doo, chairman of the Joint Chiefs of Staff. (Yonhap)