The Taliban has shot down a US military helicopter in eastern Afghanistan, killing at least 30 Americans, most of them belonging to the same elite unit as the Navy SEALs who killed Osama bin Laden.
Seven Afghan commandos and a civilian interpreter also died, US officials said, in the deadliest single loss for American forces in the decade-old war against the Taliban.
The downing was a stinging blow to the lauded, tight-knit SEAL Team months after its crowning achievement.
It was also a heavy setback for the US-led coalition as it begins to draw down thousands of combat troops fighting what has become an increasingly costly and unpopular war.
None of the 22 SEAL personnel killed in the crash were part of the team that killed the al Qaida leader in a May raid in Pakistan, but they belonged to the same unit. Their deployment in the Friday night raid in which the helicopter crashed would suggest that the target was a high-ranking insurgent figure.
Special operations forces, including the SEALs and others, have been at the forefront in the stepped up strategy of taking out key insurgent leaders in targeted raids.
The strike is also likely to boost the morale of the Taliban in a key province that controls a strategic approach to the capital Kabul.
The Taliban claimed they downed the helicopter with a rocket while it was taking part in a raid on a house where insurgents were gathered in the province of Wardak.
"Their deaths are a reminder of the extraordinary sacrifices made by the men and women of our military and their families, including all who have served in Afghanistan," US president Barack Obama said in a statement, adding that his thoughts and prayers go out to the families of those who perished.
The dead included 22 SEALs, three Air Force air controllers, seven Afghan Army troops, a dog and his handler, a civilian interpreter and the helicopter crew.