A small number of British soldiers “disobeyed orders and were absent without leave” and may have traveled to Ukraine “on a personal basis”, the British military said.
An army spokesman said: ‘We strongly encourage them to return to the UK.
It comes after Defense Secretary Ben Wallace said the soldiers could be prosecuted for desertion if they traveled to Ukraine to fight Russian forces.
Ministry of Defense (MoD) chiefs have banned all military personnel from traveling to Ukraine “until further notice”.
“This applies whether the service person is on leave or not. Personnel traveling to Ukraine will face disciplinary and administrative consequences,” a defense ministry spokesperson said.
Mr Wallace pointed out that serving soldiers who have already traveled to the war zone will face a court-martial upon their return.
He also warned other Britons not to travel to Ukraine, telling them they would not be there for “a selfie and six weeks” but in the war “for real”.
In the Commons, Mr Wallace said any serving personnel who have traveled to Ukraine ‘will break the law and be prosecuted on their return for being absent without leave or deserting’.
For other Britons, he said “we strongly advise against joining these forces” in Ukraine.
“The Ukrainians are very clear: you show up, you’re in it for the whole game. You’re not there for a selfie and six weeks you’re there for real,” he said,
“I think we have already seen some people at the borders find that this may not be the right option to go.
The UK’s stance on Brits joining the resistance to Vladimir Putin’s invasion has forced ministers to backtrack on comments from Foreign Secretary Liz Truss, who said she would ‘absolutely’ support the volunteers who would go to Ukraine to fight.
Ministers’ concerns about the British being caught up in the fighting were underlined by Cabinet Minister Grant Shapps, who said it risked creating a “dangerous situation” with the Russians.
Mr Shapps told troops ‘you can’t just get up and leave’ after a 19-year-old Coldstream Guard was reportedly among four missing British soldiers who feared they had traveled to fight Russia.
The Transport Secretary stressed there was a “big difference” between the individuals making the potentially illegal decision and the UK sending troops to fight alongside the Ukrainians.
Ministers ruled out such a move for fear it would trigger a world war, instead pledging to provide defensive weapons to repel Moscow’s troops.
A teenage Coldstream Guardsman, based at Windsor Barracks, wrote a farewell letter to his parents and bought a ticket to Poland over the weekend with the aim of crossing over to Ukraine, according to The Sun.
Mr Shapps told ITV’s Good Morning Britain: ‘You can’t go and fight if you’re in the British army, you can’t just get up and go and fight.
“Of course, this is inappropriate behavior and one would expect the military to have very, very strict rules in place, as they do.”