SEOUL, South Korea — North Korea said today it 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.

— The Associated Press