Russian medics who treated radiation victims after a military explosion in the Arctic had no protection and now fear they were irradiated themselves.

Two of the medics in Arkhangelsk spoke about the victims’ evacuation, on condition of anonymity.

Five nuclear engineers died on 8 August when an “isotope-fuel” engine blew up at the Nyonoksa Test Range, officials said. Six other people were injured.

President Vladimir Putin said the test involved a new weapon system.

Officials gave few details about the accident. On 14 August Russia’s weather service Rosgidromet revealed that radiation levels had spiked 16 times above normal, in Severodvinsk, a city 29 miles east of Nyonoksa.

Experts in Russia and the west say the test was most likely linked to the new 9M730 Burevestnik nuclear-powered cruise missile that last year Mr Putin said will give the missile “unlimited” range.