North Korean state media referred to the birthday of North Korean late founder Kim Il-sung as the Day of the Sun on Monday after stopping using the term in recent weeks while calling it "the April holiday."

Kim's birthday, April 15, has been revered as the Day of the Sun in North Korea and celebrated as one of the secretive country's most important national holidays, along with the birthday of his late son and successor Kim Jong-il in February. The North's founder died of heart failure in 1994 at age 82.

But in the run-up to his 112th birthday this year, North Korean state media had referred to it as "the April holiday" or "the spring holiday in April" instead of the Day of the Sun in recent months, spawning speculation that the incumbent leader Kim Jong-un may be cautious about an excessive idolization of his grandfather.

The North's state media called his birthday the Day of the Sun again in its Monday reports, while calling on people to show loyalty to Kim Jong-un, who it said has inherited the revolutionary ideology from the forefathers.

Senior party and government officials laid floral baskets before the statues of the two late leaders on Mansu Hill on Sunday "on the occasion of the significant Day of the Sun," the Korean Central News Agency reported.

Seoul's unification ministry earlier said it is "unusual" for North Korean state media to have been referring to Kim's birthday as the April holiday" in recent weeks.

When asked if North Korea is viewing Kim's birthday as less important than before, the ministry said it should comprehensively look at media reports coming out until April 15 in a bid to correctly assess the situation.

Kim Il-sung is known as the role model of the North's incumbent leader. But at a year-end party meeting, Kim Jong-un scrapped a decadeslong policy of seeking unification with South Korea, a legacy of his grandfather, and defined inter-Korean ties as those between "two states hostile to each other."

Koo Byoung-sam, spokesperson at the unification ministry, declined to comment on the reemergence of the Day of the Sun reference in the North's state media.

"North Korea used the term in the Rodong Sinmun, its main newspaper, but there seems to be no difference from its previous pattern, where the country capitalized on April 15 as a chance to strengthen internal unity by idolizing Kim Il-sung and highlighting loyalty to Kim Jong-un," he said. (Yonhap)