The Russian foreign ministry said it had told Norway’s envoy Robert Kvile that Oslo should stop persecuting “Russian citizens on the basis of their nationality”.

Last week a Russian man was sentenced to 90 days in jail in Norway for flying a drone over Norwegian territory in violation of a ban adopted in response to Moscow’s offensive in Ukraine.

Nearly a dozen Russians have been arrested in Norway in recent weeks for violating the flight ban or the ban on photographing sites deemed sensitive, as the country has heightened security around strategic infrastructure.

“We have noted that the sentences against the Russians are politically motivated and have nothing to do with the principles of fair and unbiased justice,” the Russian foreign ministry said in a statement.

Now Europe’s main supplier of natural gas, Norway has been on high alert since mysterious unmanned aircraft were spotted near strategic sites, including oil and gas platforms far offshore, over the past few weeks.