A military helicopter has crashed in southern Afghanistan, killing nine soldiers from the NATO-led international force fighting the Taliban.
Four other people were injured.
It is not yet clear what caused the crash.
At least 529 troops have been killed so far this year in Afghanistan
Meanwhile, British troops have transferred responsibility for security in the Sangin district of southern Afghanistan to American forces, leaving an area where Britain has suffered its worst losses since the 2001 invasion.
Control was formally handed to the United States Marine Corps on Monday.
The military insists the handover is not an admission of defeat after four years of fighting the Taliban.
The BBC reports 1000 Royal Marines and other personnel are being redeployed to central Helmand province.
More than 100 British troops have died in Sangin district, accounting for nearly a third of their 337 casualties since the invasion of Afghanistan to topple the Taliban regime following the September 11 attacks.
Defence Secretary Liam Fox said British troops should be "proud of their achievements".
He said Sangin was "one of the most challenging areas of Afghanistan".