The men intercepted meetings between buyers and sellers of masks, stealing as many as 100,000.
Three men accused of stealing 100,000 masks designed to protect against the coronavirus have been arrested by police in Ukraine.
Several people who were selling masks were attacked by armed thieves, the Ukrainian prosecutor's office said in a statement, during meetings between resellers and potential buyers.
Iryna Venedyktoval, Ukraine's general prosecutor, said the men presented themselves as members of the security forces and asked their victims to lie on the ground before taking the masks.
The suspects, aged from 26 to 42, face up to 10 years in prison. The value of the stolen goods is estimated at around 44,000 euros.
In the midst of the coronavirus crisis, medical masks have become a rare commodity in Ukraine, which is also taking drastic measures to stem the pandemic.
It is currently almost impossible to find them in pharmacies and their prices have soared in some stores, AFP reported.
On Tuesday, cafes, restaurants, cultural places and shopping centers in the country were closed.
From Wednesday, the country's three metro and bus networks, as well as trains and planes, will also be suspended.
Several Ukrainian businessmen have announced they would donate medical equipment to hospitals to fight the pandemic in Ukraine, AFP added.
According to the latest official report, Ukraine counts seven confirmed cases of coronavirus and one dead.