The South Korean military has dismissed North Korea’s claims that a drone invaded its airspace earlier this month after taking off from the South’s Baengnyeong Island near the western de facto maritime border.

At a press briefing Monday, spokesperson Lee Sung-joon from Seoul’s Joint Chiefs of Staff(JCS) said the North’s “unilateral” claims were not worth a response.

The spokesperson said the North has invaded South Korean airspace via drone more than a dozen times in the past decade.

Responding to a recent statement from Kim Yo-jong, the powerful sister of regime leader Kim Jong-un, who said she would like to see South Korea’s response if an unidentified drone flew over its capital, Lee said the military would take appropriate measures to protect its people and their property.