According to one of dozens of documents leaked online, the UK is among a number of countries with military special forces operating in Ukraine.
It confirms what has been the subject of quiet speculation for over a year.
The leaked files, some marked “top secret”, paint a detailed picture of the war in Ukraine, including sensitive details of Ukraine’s preparations for a spring counter-offensive.
The US government says it is investigating the source of the leak.
According to the March 23 document, the UK has the largest contingent of special forces in Ukraine (50), followed by fellow NATO states Latvia (17), France (15), the US (14) and the Netherlands (1). .
The document does not say where the forces are or what they are doing.
The workforce may be small and will undoubtedly fluctuate. But special forces are very effective by nature. Their presence in Ukraine is likely to be seized upon by Moscow, which has argued in recent months that it is confronting not only Ukraine but also NATO.
In line with its standard policy on such matters, the UK Ministry of Defense has not commented, but in a tweet said on Tuesday that the leak of alleged classified information had revealed what it called a “serious level of inaccuracy.”
“Readers should be careful about making allegations that have the potential to spread misinformation,” the report said.
It did not elaborate or suggest which specific documents it was referring to. However, Pentagon officials say the documents are genuine.
One document, detailing the number of casualties in Ukraine on both sides, appeared to have been manipulated.
British special forces are made up of several elite military units with different areas of expertise and are regarded as some of the most capable in the world.
The UK government has a policy of not commenting on its special forces, unlike other countries including the US.
The UK has vociferously supported Ukraine and is the second largest donor of military aid to Kiev after the US.
US Defense Secretary Lloyd Austin said the Justice Department had opened a criminal investigation and he was determined to find the source of the leak.
“We will continue to examine and turn over every stone until we find the source of this and its size,” he said.
