North Korean media outlets have stayed mum on leader Kim Jong-un's whereabouts without putting out any reports on his public activity amid persisting speculation over his health.

Speculation about Kim's health problems spiked after CNN reported earlier this week, citing a US official, that Washington is looking into intelligence that Kim is in "grave danger" after a surgery.

North Korea's state media have recently put out reports on Kim sending diplomatic letters and conveying gifts to honored citizens but stopped short of providing reports or photos featuring his public activity.

On Wednesday, state media said Kim had sent another message to Syrian President Bashar al-Assad, expressing gratitude for congratulating him on the anniversary of his late grandfather and national founder Kim Il-sung's birthday.

No reports, however, on the leader's "field guidance" trips or photos on his public activities have been released by state media for nearly two weeks.

Kim was last seen in state media on April 11 presiding over a political bureau meeting of the ruling Workers' Party, calling for strict measures against the coronavirus.

But his absence from a key ceremony commemorating the 108th birth anniversary of Kim Il-sung on April 15 has sparked speculation over his health. He has never skipped his trip to the mausoleum since taking office in late 2011.

South Korean officials have rejected the speculation, saying no unusual signs have been detected that suggest something may be wrong with Kim's health.

Kim seems to be staying in a "local region" outside of Pyongyang, and business is going on as usual in the North, according to Cheong Wa Dae officials. Some media reports speculated that Kim might be in the eastern coastal town of Wonsan to avoid the coronavirus.

US President Donald Trump said on Thursday (Washington time) that he believes a recent CNN report on Kim's failing health was "incorrect."

It is not rare for Kim to disappear from public view for some time. The ministry handling inter-Korean affairs said that he reemerged after as long as 21 days of absence earlier this year.

In 2014, he disappeared from the public eye for about a month but reappeared limping. He was later confirmed to have had a cyst removed from his ankle.

The ministry said the North's media have scarcely disputed directly any rumors about its leader but usually released reports or photos suggesting that he remains in good health. (Yonhap)