SEOUL, South Korea — North Korea said Friday that it had test-launched new anti-aircraft missiles, as its military threatened unspecified grave steps against the U.S. and South Korea over their joint military drills that it views as an invasion rehearsal.

The official Korean Central News Agency said that leader Kim Jong Un oversaw the tests Thursday and called the missiles involved “another major defense weapons system” for North Korea.

The missile launches, North Korea’s sixth weapons testing activity this year, occurred on the same day that the U.S. and South Korean militaries concluded their annual Freedom Shield command post exercise. The 11-day training was the allies’ first major joint military exercises since the inauguration of President Donald Trump in January, and the two countries held diverse field training exercises alongside the Freedom Shield drills.

U.S. and South Korean officials describe their combined military drills as defensive in nature, but North Korea slams them as a major security threat. Hours after this year’s Freedom Shield training began on March 10, North Korea fired several ballistic missiles into the sea.
On Friday, the North Korean Defense Ministry alleged that the recent U.S.-South Korean drills involved simulations to destroy underground tunnels in the North to remove its nuclear weapons. An unidentified ministry spokesperson said the U.S. and South Korea would face consequences if they performed similar provocative actions again.

“The accumulated reckless military moves of the U.S. and the ROK, seized with the daydream that they can jeopardize the sovereignty and security of a nuclear weapons state, can undoubtedly bring the gravest consequences they do not want,” the spokesperson said in a statement carried in KCNA.

ROK is the Republic of Korea, South Korea’s official name.