SEOUL: North Korean leader Kim Jong Un ordered a strengthening of the country's defence capabilities, state media said on Friday, as he wrapped up a key party meeting with top military officials that came amid concerns about a potential nuclear test.

The meeting has been closely watched due to growing speculation that Pyongyang could conduct its first nuclear test in five years, which U.S. and South Korean officials have said could take place at "any time" now.

Kim presided over the three-day Enlarged Meeting of the 8th Central Military Commission that ended on Thursday where top officials "examined and approved an important issue of providing a military guarantee for further strengthening the country's war deterrent," official KCNA media said.

The KCNA report did not directly mention North Korea's nuclear or ballistic missile programme, but said Ri Pyong Chol, who has been leading the North's missile development, was elected as vice-chairman of the powerful Party Central Military Commission.

"(Kim) stressed the need for the entire army to ... consolidate in every way the powerful self-defence capabilities for overwhelming any hostile forces," KCNA said.

During the meeting, North Korea made a rare mention of revising its war plans, and said it decided to bolster the operational duties of its frontline units with "an important military action plan."

State media on Thursday released a photo of the North's top officials in a meeting with a map of what appeared to be the east coast of the Korean Peninsula.

In April, Kim called on the country's military to "bolster up their strength in every way to annihilate the enemy."

North Korea has tested an unprecedented number of ballistic missiles this year, including massive intercontinental ballistic missiles (ICBMs), new hypersonic missiles, and a short-range missile potentially designed for tactical nuclear weapons.