The North Korean leader is seen cutting the ribbon at the opening of a fertiliser factory in Sunchon yesterday, at a ceremony with other senior officials.

Kim was seen touring the plant and smiling and talking to people at the ceremony, but news agency Reuters said the authenticity of the pictures, released by the Korean Central News Agency, could not be verified.

It is his first public appearance since April 11. Speculation about his health ramped up after he missed the April 15 birthday celebration for his late grandfather Kim Il Sung, the country’s most important holiday, for the first time since taking power in 2011.

There were claims he was fighting for his life after heart surgery, and there were even rumours that he had died and a reportedly fake image of him in a coffin circulated social media a few days ago.

State media said workers at the factory yesterday broke into ‘thunderous cheers’ for Mr Kim, who it said is guiding the nation in a struggle to build a self-reliant economy in the face of ‘head wind’ by ‘hostile forces’.

Other senior officials present included his sister Kim Yo Jong, who many analysts predict would take over if her brother is suddenly unable to rule.

Mr Kim last appeared in public when he presided over a ruling Workers’ Party meeting to discuss coronavirus, and reappoint his sister as an alternate member of the powerful decision-making political bureau of the party’s central committee.

The possibility of high-level instability raised troubling questions about the future of the secretive, nuclear-armed state that has been steadily building an arsenal meant to threaten the US mainland while diplomacy between Mr Kim and US President Donald Trump has stalled.

Speaking to reporters at the White House, Mr Trump declined to comment about Mr Kim’s reappearance but said he would ‘have something to say about it at the appropriate time’.

State media reported Mr Kim was carrying out routine activities outside public view, such as sending greetings to the leaders of Syria, Cuba and South Africa and expressing gratitude to workers building tourist facilities in the coastal town of Wonsan, where some speculated he was staying.

South Korea’s government, which has a mixed record of tracking Pyongyang’s ruling elite, repeatedly downplayed speculation that Mr Kim, believed to be 36, was in poor health following surgery.

It was not immediately clear what caused Kim’s absence in recent weeks.

In 2014, Kim vanished from the public eye for nearly six weeks and then reappeared with a cane. South Korea’s spy agency said he had a cyst removed from his ankle.