Experts said they believed that with modern testing technology, the Russian authorities should know the answer by now.

But, increasingly, Moscow is deploying its new jet-powered drones, for which Ukraine also has limited answers. The drones now attack around the clock, targeting major businesses, data centres, railway infrastructure, medical facilities and densely populated residential neighbourhoods.

Perspective: Pneumonic plague sounds like the nightmare scenario. Strangely, it may be the more reassuring one.

Britain unveiled sanctions targeting Russian oil companies, its shadow fleet of tankers and those accused of supplying the Kremlin with goods.

Trump says Putin agreed to supply over 300,000 tons of diesel fuel immediately, with millions more tons to follow as prices soar past $6 a gallon.

Russian authorities aren’t saying much about the death of a woman who worked in a lab studying plague. But experts say any risk of contagion would be limited.

Russian authorities are keeping a tight lid on information about last week’s suspicious death of a lab worker in Siberia that has been surrounded by secrecy and claims that it could have been caused by pneumonic plague.

A global treaty signed by 197 countries — including Russia — requires reporting any death that could be a sign of an outbreak to come.

When the Siberian town of Shelekhov found itself at the center of global headlines over a plague scare, residents might have hoped to be the best informed.