PRESS ASSOCIATION -- Prime Minister David Cameron has paid tribute to the US troops killed when a helicopter crashed in Afghanistan.
Officials in Kabul said that a US helicopter carrying American and Afghan special forces had crashed in the province of Wardak, killing 38 people.
The US has not confirmed the number of dead, but reports suggest that 31 Americans, most of them from the Navy Seal unit which killed Osama Bin Laden have died.
If confirmed, it would be the worst loss of US life in an individual incident since the start of the Afghan conflict in 2001.
Mr Cameron said: "I was deeply saddened to hear of the many US military personnel who lost their lives in Afghanistan. My thoughts - and the thoughts of the whole country - are with their families and friends.
"They have made the ultimate sacrifice in helping to protect our security, and to build a more stable and peaceful Afghanistan.
"We remember too the Afghan troops who died alongside them.
"Britain, and our own armed forces serving in Afghanistan, will continue to work steadfastly alongside their US and Afghan colleagues as they help prepare Afghanistan to secure its own territory."