North Korean leader Kim Jong-un has called for full combat readiness and a change in the machinery of his troops, as he chaired a key session of the ruling Workers' Party of Korea, Pyongyang's media reported Monday.

Kim delivered a "historic speech" at the extended meeting of the party's Central Military Commission, the first of its kind in 10 months, according to the official Korean Central News Agency.

He was quoted as saying that the security situations at home and abroad have been graver than at any other time since he seized power three years ago in the wake of the death of his father, Kim Jong-il.

Although the North's armed forces have done well to protect the country, it's time to beef up combat capabilities, he added.

"Emphasizing the need for the Korean People's Army to focus all of its efforts on rounding off combat readiness this year, he said it was necessary to simplify the machinery of the KPA and indicated the direction and ways for reorganizing the machinery in such a way to realize the strategic intention of the Supreme Command any time," the KCNA said in an English-language report.

Calling on the military to be fully ready for any form of war, he clarified the methods of fighting a war with the U.S., it added without providing details.

Kim presided over the previous session of the party commission in April last year, in which the North's top officials discussed the nation's defense policy and war tactics.

In the meeting, the North decided to replace Choe Ryong-hae with Hwang Pyong-so for the post of director of the general political bureau of the KPA.

The South Korean government said Pyongyang has held a total of five extended meetings of the party's central military panel under Kim Jong-un's rule.

"We will closely monitor the outcome of the meeting this time," the unification ministry's spokesman Lim Byeong-cheol said.

On the North's show of its firepower through repeated military drills, he urged Pyongyang to halt threats and provocative acts.

"With regard to dialogue between the South and the North, our government has an open position (to hold it) under any circumstances," Lim said, reiterating that Seoul is willing to discuss every issue of mutual concern in a "comprehensive" manner regardless of the format of talks.

He stressed that the North should stop taking issue with the annual South Korea-U.S. military exercise, set to begin next week, which is a routine, defense-oriented and transparent event. (Yonhap)