Ukraine has fired UK-supplied Storm Shadow missiles at targets inside Russia for the first time, the BBC understands.
The war-torn country was previously restricted to using the long-range missiles within its own borders. Reports of the strikes come after Ukraine was given permission from Washington to fire US-supplied missiles at Russian territory.
The government has refused to comment on the reports for operational reasons, but officials confirmed Defence Secretary John Healey spoke to his Ukrainian counterpart on Tuesday night.
Ministers are likely to exercise caution in their response to the reports due to concerns over Russia"s reaction, as well as to ensure the move is not seen as being led by the UK.
Ukraine’s Defence Minister Rustem Umerov has also declined to confirm that his country has used the Storm Shadow missiles within Russian territory, but said it was “using all the means to defend our country”.
Storm Shadow is considered an ideal weapon for penetrating hardened bunkers and ammunition stores, such as those used by Russia in its war against Ukraine. The US and UK had previously not given permission, with suggestions this was related to not wanting to escalate the war.