The Government is expected to announce the withdrawal of British forces from Bosnia amid claims it is "scratching around" for troops to deploy in Afghanistan.
The UK currently has some 600 military personnel carrying out peacekeeping and reconstruction work in the Balkan state, mainly Welsh Guards based in the north-west as part of the EU's Eufor.
But Armed Forces minister Adam Ingram is expected to tell MPs that the troops are being pulled out following a decision by the EU to restructure and scale down operations.
The announcement is expected as the Prince of Wales and Duchess of Cornwall pay a visit to the Welsh Guards at Banja Luka in Bosnia to celebrate St David's Day.
The Tories quickly seized on the news, with Shadow Defence Secretary Dr Liam Fox insisting it was more evidence of "overstretch".
Earlier this week it was disclosed that 1,400 reinforcements are being sent to Afghanistan, putting extra strain on the military despite a 1,000 cut in the Iraq commitment.
"It's clear that as overstretch hits hard, the Government is having to scratch around to find anywhere from which it can withdraw troops to then send to Afghanistan," said Dr Fox.
"Our armed forces are carrying a heavy and disproportionate burden in Helmand.
"As our deployment increases, more and more of our servicemen and women are feeling the pressure.
"It's no wonder that so many are leaving the forces due to lack of time back home with their families to rest and re-train. There is only so far they can be stretched," he added.
