David Cameron has said news that six British soldiers are missing, believed dead, in Afghanistan was "desperately sad".
Five soldiers from the 3rd Battalion the Yorkshire Regiment and one soldier from the 1st battalion The Duke of Lancaster's Regiment are included in the group, who were on mounted patrol when their vehicle was struck by an explosion in Helmand.
If the soldiers are confirmed as dead, it will take the death toll of British troops in the region to 404.
Speaking in Downing Street on Wednesday morning the prime minister said: "This is a desperately sad day for our country and desperately sad of course for the families concerned.
"It is a reminder of the huge price that we are paying for the work we are doing in Afghanistan and the sacrifice that our troops have made and continue to make.
"I do believe it's important work for our national security right here at home but of course this work will increasingly be carried out by Afghan soldiers and we all want to see that transition take place.
He added: "But today we should think of the families."
Labour leader Ed Miliband said: "This is tragic news that six of our soldiers are missing. Our hearts go out to their families, friends and colleagues."
Suggested For You
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements. Learn more