The Houthi rebels who control Yemen's capital Sanaa have so far only acknowledged a handful of cases of coronavirus.
However, a quarter of the 200 patients being treated in the coronavirus unit set up by in a hospital in Sanaa have died, sources say.
The Houthis have downplayed the outbreak so far, but the limited facilities to treat the virus in Sanaa - one hospital for testing and one for treatment - have been overwhelmed.
The Houthis have now asked private hospitals to make beds available for coronavirus patients.
A doctor in Sanaa - just recovering from the virus himself - has said that he's already lost a number of colleagues to the disease.
Unconfirmed reports suggest a heavy toll on health workers, who are having to use one set of personal protective equipment for an entire shift.
The true extent of the outbreak is unknown - with many Yemenis fearful of going to hospital at all.
In the southern city of Aden - controlled by the internationally recognised government - recent weeks have seen a surge of cases, all appearing to confirm the warnings of catastrophe that aid agencies had been issuing since January.
Despite this, a UN call for emergency funding on Tuesday fell far short of its target.