Russian Foreign Minister Sergei Lavrov said Russia had the right to regard the direct involvement of Britain in strikes on Russian territory as participation in the war in Ukraine, the Interfax news agency reported.
His comments came after the Times newspaper reported on Saturday that British-made drones had been used for long-range strikes against Russia for the first time.
Following the report, Russia's embassy in London warned Britain of unspecified "consequences" for supplying drones to Kyiv. British Prime Minister Andy Burnham said on Tuesday that Britain would support Ukraine "100%" in its fight against Russia and stand by Kyiv "in its hour of need".
Moscow has previously accused British specialists of involvement in attacks on Russian territory, saying Britain's role would be taken "into account" in its response.
