The bodies of four more British soldiers were flown back to the UK on Thursday
Three British soldiers have been killed in an explosion in Afghanistan - taking the total deaths in the country since operations began to 199.
Two were from 2nd Battalion The Rifles and the third from 40 Regiment Royal Artillery, defence officials said.
The soldiers were killed while on foot patrol near Sangin in Helmand province on Thursday morning.
Defence Secretary Bob Ainsworth said the "tragedy" brought the UK close to the "sad milestone" of 200 fatalities.
'Thoughts and prayers'
Lt Col Nick Richardson, spokesman for Task Force Helmand, said: "Today has been incredibly sad for the whole of Task Force Helmand, and particularly for The Rifles battle group, with whom all three soldiers were serving.
"We will all feel the loss of these brave soldiers, but it is their family, friends and loved ones, as well as the men and women who served alongside them, who feel the greatest pain and we offer them our deepest and heartfelt condolences, thoughts and prayers."
Defence Secretary Bob Ainsworth said: "We cannot help but reflect on the toll the mission has taken on our people and their families and friends.
"But we must also keep in the forefront of our minds how important it is to the security of this country and its citizens.
"So many young men and women have been injured or given their lives to ensure that Afghanistan does not fall back into the hands of the extremists and the terrorists who seek to threaten us and our interests.
"We must succeed. And we will."
Earlier on Thursday, the bodies of four British soldiers killed in Afghanistan earlier this month were flown back to RAF Lyneham in Wiltshire.
A ceremony was held for their families followed by a procession in front of hundreds of mourners through the town of Wootton Basset.