Russia has warned its citizens that they face the “insertion of foreign objects” into their luggage when they travel to the UK.
The Russian embassy posted the claim of new “provocations” on its website as the row continues over the poisoning of former spy Sergei Skripal and his daughter Yulia in Salisbury.
It said the warning was necessary because of “the anti-Russian policy, the growing threatening rhetoric of the British, the British government’s selective actions against Russian individuals and legal entities”.
The Russian Ministry of Foreign Affairs has also issued a list of 14 new questions about the Salisbury poisoning that it says have not been answered, on top of the 27 made public on Friday.
They want to know what antidotes were administered to the Skripals, how it was determined that the nerve agent used in the attack “originated from Russia” and whether it has been produced in the UK.
Several questions focus on the involvement of French experts in the investigation.
The British government is still considering a request to allow Russian officials to visit Yulia Skripal after it was reported her condition was rapidly improving.
Her father, a former MI6 spy, remains in a critical but stable condition in hospital after being exposed to the nerve agent novichok on 4 March.
Britain expelled 23 Russian diplomats earlier this month after accusing Russia of responsibility for the attack.
Russia responded by sending the same number home from Moscow and has retaliated against similar moves by the US and many EU nations.
Additional UK diplomats were told to leave on Saturday as the Kremlin ordered Britain to cut just over 50 more of its Russia-based staff.
Russia has also accused Britain of “blatant provocation” after border force officers searched an Aeroflot plane at Heathrow.
Securities minister Ben Wallace described the search as “routine”.