Russia has summoned the British Ambassador to Moscow, Deborah Bronnert, over claims that the UK provided training to Ukrainian forces that attacked Russia’s Black Sea Fleet in Crimea last week.

The Russian Foreign Ministry presented the diplomat with a “steadfast protest” and warned her that London’s hostile actions “could lead to unpredictable and dangerous consequences,”according to a statement published on the ministry’s website on Thursday. 

“If acts of aggression that risk turning [Britain] into a direct party in the conflict continue, the British side will solely bear the responsibility for their negative consequences and the increase in tensions between our countries,” the ministry said. 

The move came after the Russian Defense Ministry claimed that British instructors led the training of Ukrainian troops who carried out aerial and seaborne drone attacks on Russian ships in Sevastopol naval base in Crimea, on Saturday. A minesweeper was damaged in the raid.

A person familiar with the matter told RT on Thursday that a group of senior Ukrainian naval officers, including ship commanders and missile specialists, had completed a two-week training course at a UK base in September. While the course was officially designated as demining training, it focused on teaching Ukrainians how to use “modern British-made unmanned underwater vehicles,” the source said.

The Russian Foreign Ministry issued a statement saying that British personnel had been helping Ukraine train frogmen and underwater demolition experts in the Black Sea ports of Ochakov and Odessa. On Saturday, the British Defense Ministry denied the allegations.