SEOUL – A communication error between South Korean and US military officials nearly led to the interception of a US military drone flying near the inter-Korean border last week, Yonhap news agency said Monday.

An unidentified official with South Korea's Joint Chiefs of Staff (JCS) told local reporters that the incident was caused by a lack of proper reporting and a reliance on informal communication habits at the working level.

The JCS investigations found that the US military notified a South Korean official in the army's 1st corps about its drone flight plan via a mobile text message on July 29, the day before a combined South Korea-US military exercise in Paju near the demilitarized zone (DMZ) separating the two Koreas.

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The South Korean official replied that there was no restriction but failed to report or share the information with superiors or higher commands because the official assumed it involved a low-altitude drone flight, which fell under the first corps' discretionary authority.

The US drone, however, flew higher than anticipated, prompting the South Korean military unaware of the approved flight to misidentify it as an unidentified flying object and prepare for a potential interception.

Official protocol requires flight plans to be submitted in advance via official documents in order to obtain approval from either the air force operations command or the ground operations command.