On Saturday, North Korean newspaper Rodong Sinmun published photos of Kim Jong Un from the May Day celebrations, thus refuting rumors about his death. The photos show Kim opening the Sunchon Phosphatic Fertilizer Factory in the city of Sunchon, north of Pyongyang.
Trump took to Twitter to express happiness on the North Korean leader's "comeback", reposting the photos.
On Saturday, South Korean state news agency Yonhap reported that Kim had made his first public appearance in 20 days.
The North Korean leader’s previous appearance took place on 12 April. After media reports about Kim’s surgery, some news outlets reported about the leader's alleged death.
On Monday, Trump said he had "a very good idea" about Kim’s status, but could not publicly disclose it. Trump also said he wished the North Korean leader well.