North Korea has eliminated references to reunifying with South Korea from its constitution, according to a document reviewed Wednesday, marking a clear shift toward a more hostile policy towards Seoul.

North and South Korea remain technically at war because their 1950-53 war ended in an armistice, not a peace treaty.

Pyongyang's constitution had previously contained a clause stating that it aimed "to realize the unification of the motherland".

That reference no longer appears in the latest version, presented on Wednesday by a professor during a news conference at South Korea's Unification Ministry and subsequently seen by AFP.

North Korean officials considered constitutional amendments at a major congress in March, where leader Kim Jong Un labelled Seoul as the "most hostile state".