There has been a rush to buy medical iodine in Russia’s far north, following a brief radiation spike linked to a rocket accident, Russian media report.
Pharmacies’ stocks of iodine are reported to be running out in the cities of Arkhangelsk and Severodvinsk.
Iodine can block the thyroid gland’s take-up of radioactive iodine, but the pills can also cause medical problems.
Two people died and six were injured in Thursday’s accident at a test site. But the military has given few details.
The authorities say radiation levels were higher than normal for about 40 minutes around the Nyonoksa naval test range, but then returned to normal.
The defence ministry said a liquid-fuel rocket engine had exploded, but it did not specify the system involved.
The navy is now keeping all shipping out of nearby Dvina Bay, on the White Sea, for a month. Officials did not explain the temporary closure of the bay.
The village of Nyonoksa is about 47km (29 miles) west of Severodvinsk, which has a population of nearly 200,000. Severodvinsk has a shipyard that builds and repairs nuclear submarines for Russia’s Northern Fleet.
A news website for the Arkhangelsk region, 29.ru, said pharmacies’ stocks of iodine pills were running out in Arkhangelsk on Thursday evening.
The website also said medics who evacuated the injured at Nyonoksa wore chemical and nuclear protection suits.
There was a rush on iodine stocks during the 1986 Chernobyl nuclear disaster in Ukraine, which sent a huge plume of radiation across Europe.
It is the second accident involving Russia’s military this week.
On Monday, one person was killed and eight others were injured in a blaze at an ammunition dump in Siberia.
Earlier on Thursday there were reports of a fire at a military facility near Nyonoksa. Telegram-based media outlet Mash said radiation levels in the village were three times higher than normal.
The defence ministry insisted that “there have been no harmful chemicals released into the atmosphere, the radiation levels are normal”.
Nyonoksa carries out tests for virtually every missile system used by the Russian navy, including sea-launched intercontinental ballistic missiles, cruise missiles and anti-aircraft missiles.