North Korean leader Kim Jong Un led a salvo missile launch to test the country’s “Nuclear Trigger’ system” for the first time on Monday, according to state media, while blaming the U.S. and South Korea for raising tensions.

The drills featured training on raising the war alert in the lead up to the launch of four 600mm multiple launch rocket system (MLRS) rockets at once using the “national nuclear weapon comprehensive control system,” a test of Kim’s ability to maintain command and control over nuclear weapons spread across the country in a crisis.