South Korea's intelligence agency also said Pyongyang received help from Russia for its successful launch of a reconnaissance satellite this week.

North Korea had sent data to Russia on launch vehicles used in two failed previous satellite launches, and Moscow had offered its analysis of the data, Yoo Sang-bum, a member of the parliamentary intelligence committee, said after a briefing by the spy agency.

The launch was "successful", with the satellite entering orbit around the Earth, and North Korea could launch additional satellites and conduct a nuclear test next year, Youn Kun-young, another committee member, said.

The last time the secretive state tested a nuclear bomb was in 2017 - at a facility it apparently demolished ahead of talks between then US president Donald Trump and North Korean leader Kim Jong Un.

In 2018, Sky News correspondent Tom Cheshire was the only British broadcaster invited to watch a series of demolition explosions at the Punggye-ri test site ahead of the meeting.

North Korea state media claimed the site had been completely dismantled in the blasts "to ensure the transparency of discontinuance of nuclear tests".

South Korea suspended part of a military agreement after the North defied warnings to launch its spy satellite.

The move means Seoul will step up surveillance along its fortified northern border - negating a clause laid out in a 2018 pact between the nations.

Critics had argued the deal had only weakened South Korea's ability to monitor the northern border - while North Korea had violated the agreement.

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Kim calls for more satellite launches

Images published in North Korean state media on Tuesday showed what appeared to be Mr Kim watching a rocket launch from a base.

According to the KCNA news agency, the North Korean leader was later briefed on the satellite's operations and viewed pictures taken above the US territory of Guam in the Pacific.

He emphasised the need for more satellites on different orbits to give his forces "abundant valuable real-time information about the enemy and further promote their responsive posture", the agency added.

After adjustments, its reconnaissance mission is due to start on 1 December.

It was the first launch since Mr Kim met Vladimir Putin at a Russian space facility in September, where the Russian president promised to help North Korea build more satellites.