PYONGYANG, March 7 (Xinhua) -- Kim Jong Un, the supreme leader of the Democratic People's Republic of Korea (DPRK), has supervised a ballistic rocket launching drill of the Korean People's Army (KPA) on spot, said the Korean Central News Agency (KCNA) Tuesday.

Involved in the drill were Hwasong artillery units of the KPA Strategic Forces "tasked to strike the bases of the U.S. imperialist aggressor forces in Japan in contingency," said the report.

Kim learned in detail about the preparations for fire strike" while going round the ballistic rocket launching ground," said the report.

"He appreciated that Hwasong artillery units of the Strategic Force are very good at organizing and commanding fire strikes and strictly ensuring rapid and simultaneous fire strikes," said the report, adding that four rockets were launched simultaneously.

Kim described the rockets launch accuracy like "acrobatic flying corps in formation," said the report.

He also ordered the KPA Strategic Force to "keep highly alert as required by the grim situation in which an actual war may break out anytime, and get fully ready to promptly move, take position and strike so that it can open fire to annihilate the enemies once the Party Central Committee issues an order," according to the report.

The rocket launching drills were conducted on Monday on the eastern coast of DPRK, said earlier media reports from outside DPRK.

The drills were conducted when the United States and South Korea are conducting a two-month long large scale joint military exercise.