North Korean leader Kim Jong-un reportedly called for consistent efforts to bolster the country’s nuclear capabilities as he oversaw a joint strike drill on Thursday to test ballistic missiles and long-range artillery.

The North’s state Korean Central News Agency(KCNA) said Friday that Kim directed the test the previous day to check the performance of a 600-millimeter multilayer rocket system and the Hwasongpho-11-Ka tactical ballistic missile. 

The KCNA said the drill’s aim was to familiarize military units with the operation of the weapons. 

Overseeing the test, Kim reportedly stressed the need to perfect the combat readiness of the North’s nuclear arsenal, saying the country should continue its efforts to steadily improve its weapons’ efficiency and long-range precision striking capabilities. 

The KCNA said that ahead of the test, there was an inspection of a nuclear defense system the North calls the “nuclear trigger.” 

South Korea’s Joint Chiefs of Staff said Thursday that it detected the launch of multiple short-range ballistic missiles of various types from the city of Wonsan on the North’s east coast between 8:10 and 9:20 a.m.