Three British ex-special forces troops are feared dead following a Russian airstrike near the Polish border.
It is believed they died instantly in the cruise missile blasts after a deadly Russian airstrike on a base near to Poland - which neighbours Ukraine.
The attack is understood to have killed “many scores more” than was previously reported, with possibly well over 100 dead.
Sources told the Daily Mirror the three men were not part of the foreign fighters unit that was being trained at the now destroyed Yavoriv base, which is just six miles from the Polish border.
It is not known which branch of special forces they had served in.
Up to 30 cruise missiles were unleashed on the base - which is located 35 miles from the western Ukrainian city of Lviv.
It is believed all of the missiles were fired by six Russian bombers from within Russian.
However, a number of them were shot down by Ukrainian ground defence systems.
UK Foreign Office sources insisted on Sunday that they were unaware of any British casualties among the dead.
The British MoD also said there were no serving personnel killed or injured in the explosions.
A source told the Daily Mirror: “There were many more killed within the site than has been claimed and bodies are still being found.
“I do not believe the three British ex-military personnel would have known anything about it, fortunately.
“This is extremely sensitive as there are believed to be no serving British military personnel inside Ukraine as politically that would be extremely controversial.”
Witnesses have described how the attack at 5.45am “turned the sky red.”
Hours after the attack, ambulances were still rushing to the scene.
Roads leading to the facility were blocked with checkpoints and authorities were conducting search-and-rescue operations.
The base is known as the International Peacekeeping and Security Center.
The UK Foreign Office said tonight it is urgently investigating.
It advises against all travel to Ukraine.
