Pyongyang successfully put a military spy satellite into orbit last month and has since claimed it was providing images of major US and South Korean military sites.

It has not yet disclosed any of the satellite imagery it claims to possess but warned on Saturday that any attack on its space asset would be considered a "declaration of war".

The official Korean Central News Agency (KCNA) said on Sunday that the newly formed reconnaissance satellite operation office had begun its mission on December 2 and would operate as "an independent military intelligence organization".

The office will report its acquired information to the reconnaissance bureau at the army and other major units, KCNA added.

The report said that the North's defence ministry expressed its war deterrence "would assume more perfect military posture".

North Korea is barred by successive rounds of UN resolutions from tests using ballistic technology, and analysts say there is significant technological overlap between space launch capabilities and the development of ballistic missiles.

Experts have said putting a working reconnaissance satellite into orbit would improve North Korea's intelligence-gathering capabilities, particularly over South Korea, and provide crucial data in any military conflict.

The North's launch of "Malligyong-1" was Pyongyang's third attempt at putting such a satellite in orbit, after two earlier failures.

Seoul has said the North received technical help from Moscow, in return for supplying weapons for use in Russia's war with Ukraine.