North Korea has warned its citizens to stay indoors over fears that "yellow dust" which blows in from China could bring coronavirus with it.
The streets of the capital Pyongyang were reported to be virtually empty on Thursday following the warning.
The secretive state claims to be coronavirus-free but has been on high alert since January with strict border closures and restrictions on movement.
There is no known link between the seasonal dust clouds and Covid-19.
However, they are not the only country to suggest a link. The BBC's Disinformation Team notes Turkmenistan also alleged virus-laden dust was the reason citizens were being told to wear masks. They have denied trying to cover up an outbreak.
'Invading malicious viruses'
State-controlled Korean Central Television (KCTV) broadcast special weather segments on Wednesday, warning of an influx of the yellow dust the next day. It also announced a nationwide ban on outdoor construction work.
Yellow dust refers to sand from Mongolian and Chinese deserts that blows into North and South Korea at certain times of the year. It is intermingled with toxic dust that for years has raised health concerns in both countries.
On Thursday, the Rodong Sinmun newspaper, a government mouthpiece, said “all workers… must clearly recognise the danger of invading malicious viruses” in response to the dust cloud, the BBC's Disinformation Team noted.
Embassies also reported receiving a warning about Pyongyang's dust concerns.
The Russian Embassy in Pyongyang said on its Facebook page the North Korean foreign ministry had warned it and other diplomatic missions and international organisations in the country about the dust storm, recommending all foreigners stay at home and tightly close their windows on Thursday.
Could dust clouds bring in Covid-19?
North Korean state media has reasoned that research linking the coronavirus to airborne transmission means it "should take the incoming flow of yellow dust seriously", reported the specialist news site NK News
The US Centres for Disease Control has said coronavirus can remain suspended in the air “for hours”. However, it also says it is extremely rare for someone to be infected this way - especially outdoors. The main way people get infected is from standing in close proximity to someone who is infected who then coughs, sneezes or talks, spreading the virus through droplets.
Media in neighbouring South Korea has also dismissed the suggestion that yellow dust from China could spread Covid-19 to the North as impossible, according to NK News.
Despite claiming the country has no cases of coronavirus, there are deep fears about Covid-19 in North Korea and leader Kim Jong-un has been holding high-level meetings to ensure tight restrictions remain in place.
Analysts have said it is highly unlikely that North Korea has not experienced any coronavirus cases at all.
The dust had cleared from the Korean peninsula by Friday and was forecast to stay that way on the weekend.