UK denies its special forces are operating in Ukraine

Reported US intelligence leak claims as many as 50 UK special forces personnel have been sent to the country

A Ukraine army cadet takes part in a training session with members of Britain's Armed Forces in southern England. AFP

The Ministry of Defence has warned against taking claims about UK forces operating in Ukraine at “face value” after allegedly classified US documents were leaked online.

Reports suggest that a document, dated March 23, indicates as many as 50 UK special forces personnel are deployed in the country alongside other western special forces.

But the document reportedly does not state where the British forces are located or what they are doing.

A statement posted on the Ministry of Defence’s Twitter page said: “The widely reported leak of alleged classified US information has demonstrated a serious level of inaccuracy.

“Readers should be cautious about taking at face value allegations that have the potential to spread disinformation.”

Chris Meagher, a spokesman for the Pentagon, has urged caution in “promoting or amplifying any of these documents”, adding that “it does appear that slides have been doctored”.

Reports suggest the documents may first have been published in a chat room on Discord, a social media platform popular with gamers.

According to one member of the chat, an unidentified poster shared documents that were allegedly classified, first typing them out with the poster's own thoughts, then, as of a few months ago, beginning to post images of papers with folds in them.

The posts appear to have gone unnoticed outside the chat group until a few weeks ago, when they began to circulate more widely on social media.

Associated Press could not independently confirm many details shared by the person, and the original chat room has been deleted.

Asked on Monday if the US government was effectively waiting for more intelligence documents to show up online, National Security Council spokesman John Kirby said: “The truth and the honest answer to your question is: We don't know. And is that a matter of concern to us? You're darn right it is.”

In other information allegedly contained in the leaked documents, Serbia, the only country in Europe that has refused to sanction Russia for its invasion of Ukraine, agreed to supply arms to Kyiv or has sent them already.

The classified Pentagon document, a summary of European governments' responses to Ukraine's requests for military training and “lethal aid” or weapons, was among dozens posted online in recent weeks in what could be the most serious leak of US secrets in years.

Entitled Europe: Response to Ongoing Russia-Ukraine Conflict, the document lists the “assessed positions” of 38 European countries on Ukraine's requests for military assistance.

The chart showed that Serbia declined to provide training to Ukrainian forces, but had committed to sending lethal aid or had supplied it already. It also said Serbia had the political will and military ability to provide weapons in the future.

The US Defence Department is investigating who is responsible for the intelligence leaks, which started weeks ago and have covered everything from information on its allies to casualty numbers.

Some of the files, including on casualties, appear to have been doctored, pointing to attempts spread disinformation by Russia.