North Korean leader Kim Jong-un called for intensifying "practical actual war drills" during a visit to a military training base, state media said Thursday, as a joint military exercise between South Korea and the United States was under way.

During the visit to the base in the country's western region Wednesday, Kim inspected training facilities and guided the actual maneuvers of military units, the official Korean Central News Agency said.

The visit came two days after South Korea and the US began their annual Freedom Shield exercise Monday to strengthen deterrence against North Korea's nuclear and missile threats. The North has condemned the joint exercise, warning the countries will pay a "dear price."

"He set forth the important tasks for intensifying the practical actual-war drills ensuring the victory in a war," the KCNA said.

Kim also instructed the military to beef up drills to improve its combat capabilities to contain enemies with "overwhelming force" and their "slightest attempt to ignite a war," the KCNA said in an English-language dispatch.

State media photos showed Kim observing the drills with binoculars and taking a shooting position with what appeared to be an AK-74 rifle.

The military exercise between the South and the US comes as North Korea has ramped up weapons tests in recent months with the launches of cruise missiles from land and sea and artillery firing near the tense western sea border.

Pyongyang has long denounced such joint military drills as rehearsals for an invasion. Seoul and Washington have rejected the claims, saying their military exercises are defensive in nature.

"Our military will maintain a steadfast readiness posture, and respond overwhelmingly under the principle of (punishing) immediately, strongly and until the end if North Korea undertakes a provocation," defense ministry spokesperson Jeon Ha-kyou told a briefing. (Yonhap)