The official state news agency says archaeologists "reconfirmed" the existence of a "unicorn lair" in Pyongyang, once used by an ancient Korean king.

The Korean Central News Agency reports that archaeologists made the extraordinary discovery when they spotted a rectangular rock carved with the words "unicorn lair" 200m from the city's Yongmyong temple.

The report quotes Jo Hui Sung, director of North Korea's history institute, explaining how the find tallies with information in history books from the 16th century.