Japanese Prime Minister Shinzo Abe has said he was aware of reports on the health of North Korean leader Kim Jong-un and was paying close attention to developments.

Mr Abe made the comment in a session of parliament.

Rumours and speculation over Mr Kim's health began after he did not appear in public at a key state holiday on 15 April.

He has since remained out of sight.

South Korea's minister for North Korean affairs said Mr Kim may have missed the event because of concerns over the coronavirus, not because he is ill. 

His absence from public ceremonies on the birth anniversary of his grandfather and founder of the country, Kim Il-sung, was unprecedented. 

South Korean officials have emphasised that they have detected no unusual movements in North Korea and have cautioned against reports that Mr Kim may be ill. 

North Korea has said it has no confirmed cases of the coronavirus, but given the fact that the country has taken stringent steps to head off an outbreak, Mr Kim's absence from the ceremonies is not particularly unusual, Unification Minister Kim Yeon-chul, who oversees North Korea engagement, said.

South Korea's minister for North Korean affairs said Mr Kim may have missed the event because of concerns over the coronavirus, not because he is ill. 

His absence from public ceremonies on the birth anniversary of his grandfather and founder of the country, Kim Il-sung, was unprecedented. 

South Korean officials emphasise they have detected no unusual movements in North Korea and have cautioned against reports that Mr Kim may be ill. 

North Korea has said it has no confirmed cases of the coronavirus, but given the fact that the country has taken stringent steps to head off an outbreak, Mr Kim's absence from the ceremonies is not particularly unusual, Unification Minister Kim Yeon-chul, who oversees North Korea engagement, said. 

"It is true that he had never missed the anniversary for KimIl Sung’s birthday since he took power, but many anniversary events including celebrations and a banquet had been cancelled because of coronavirus concerns," he told a parliamentary hearing. 

He said there were at least two instances since mid-January where the North Korean leader was out of sight for nearly 20 days. "I don’tt hink that’s particularly unusual given the current(coronavirus) situation." 

US President Donald Trump said yesterday he has a good idea how Mr Kim is doing and hopes he is fine, but would not elaborate. 

North Korea had cancelled some large events, and imposed a border lockdown and quarantine measures in an effort to prevent an outbreak of the coronavirus. 

But if Mr Kim is hiding out due to fears surrounding Covid-19, it would "puncture a hole in the state media narrative of how this crisis has been perfectly managed", said Chad O'Carroll, CEO of Korea Risk Group, which monitors North Korea. 

"If he is merely trying to avoid infection, it should theoretically be very easy to release photos or videos of a healthy-looking Kim," he said. 

An source familiar with US intelligence reporting said it was entirely possible Mr Kim had disappeared from public view to avoid exposure to Covid-19 and the sighting of his presidential train in the coastal resort area of Wonsan did suggest he may be there or have been there recently. 

But the source said that since there was no authoritative backing for such a conclusion, US agencies were also still considering the possibility Mr Kim might be ill, even seriously. 

While North Korean state media have not reported on Mr Kim’s whereabouts since he presided over a meeting on 11 April, they have carried near-daily reports of him sending letters and diplomatic messages suggests he is still carrying out his duties as leader. 

"I agree with the South Korean government's assessment that there is no reason to think Kim Jong-un is not performing his duties," said Rachel Minyoung Lee, a former North Korea open source intelligence analyst for the US government. 

"That said, I would not read too much into letters signed by Kim Jong-un. I would guess that most of them are not written by him anyway."