The South Korean military was not aware of a U.S. Air Force B-52 strategic bomber deployment last month that took place in the vicinity of the country, officials said Monday.

According to Pacific Air Forces, strategic bomber crews and support airmen at Andersen Air Force Base in Guam conducted eight joint and bilateral training exercises across the Indo-Asia-Pacific region from June 13 through June 20.

The exercises involved flying the nuclear capable B-52 Stratofortress for a training mission in the vicinity of Korea and Japan. 

Boeing’s subsonic bomber is capable of carrying up to 32 metric tons of weapons and has a combat range of over 14,000 kilometers without aerial refueling.

The aircraft had been deployed to the Korean Peninsula in January, in what local observers suspected was a show of force as a warning in response to North Korea’s nuclear test on Jan. 6.

Pyongyang last month pushed ahead with what is assessed to be the first successful launch of its Musudan intermediate-range ballistic missile, leading experts to believe that recent training is aimed to warn against the North’s nuclear and missile ambitions. Musudan is expected to have a maximum range that would put the U.S.’s Guam base within its range.

But while the training is believed to have taken place near the Korean Peninsula, the Joint Chiefs of Staff was oblivious to its presence.

A JCS official said that the U.S. military has not notified them of the details of the exercise, particularly whether or not the “vicinity” indicates that the aircrafts may not have flown exclusively over international waters.

He said that while it is not “common” for the U.S. military to conduct training near the peninsula without first telling its ally, it is not unprecedented.

A personnel member familiar with matters related to U.S. Forces in Korea said the U.S. military is not obligated to alert local forces if the training takes place over international waters, not directly over the country’s territory itself.

The Korean liaison to the USFK was not aware of the situation’s details and refrained from commenting on the matter.

By Yoon Min-sik (minsikyoon@heraldcorp.com)