Six soldiers are missing, believed killed, after an armoured vehicle was caught in an explosion in Afghanistan, the Ministry of Defence in the UK said today.
The group - which included five soldiers from the 3rd Battalion the Yorkshire Regiment and one from the 1st Battalion The Duke of Lancaster's Regiment - was on a mounted patrol when their Warrior Armoured Fighting Vehicle was struck.
If the servicemen are confirmed dead, it would take the total number of British forces personnel or MoD civilians who have died while serving in the war-torn region to more than 400 since the start of operations in October 2001.
Defence Secretary Philip Hammond said: "This tragic incident brings home to us the dangers that are faced on a daily basis by the men and women of our Armed Forces deployed in Afghanistan.
"My thoughts are with the families and friends of the six soldiers who are missing, believed killed and also with their colleagues, both in Afghanistan and the UK, whose brave work continues or is about to start.
"I utterly condemn those responsible for this incident who will ultimately fail to derail a mission that is protecting our national security at home and making real progress in Helmand Province - a testament to the bravery, commitment and professionalism of our Armed Forces.
"We should never forget those who have lost their lives in Afghanistan to protect our national security.
"It is because of the continuing efforts of our Armed Forces, working alongside the Afghan National Security Forces, that we are on course to build an Afghanistan that can stand on its own two feet when UK combat operations cease at the end of 2014 and never again becomes a haven for international terrorism."
Chief of Defence Staff General Sir David Richards said: "I was deeply saddened by the news of this incident and that six soldiers are believed to have lost their lives doing what is a dangerous but important job.
"Increasingly the Afghans themselves are taking the lead in providing security across Helmand. This transition is allowing Afghans to gain the confidence to reject the Taliban and live normal lives.