North Korean leader Kim Jong Un visits the completed Suchon phosphate fertilizer factory in South Pyongan province in this photo released May 2, 2020. (Photo: KCNA)

The North reported that Mr. Kim had attended the opening of a fertilizer factory and released pictures it said showed the leader cutting a ribbon at the ceremony on Friday in Sunchon, north of Pyongyang.

Rumors about Mr. Kim's health have been swirling since his no-show at April 15 celebrations for the birthday of his grandfather, the most important day in North Korea's political calendar.

South Korea's Unification Ministry said "groundless" speculation about Mr. Kim had caused "unnecessary confusion," calling for more careful consideration in the future.