President Barack Obama is mourning the deaths of 31 U.S. special operations troops in a helicopter crash in Afghanistan.
He says it's a reminder of the "extraordinary sacrifices" being made by America's military and its families.
An American official says the helicopter appears to have been shot down Saturday in eastern Afghanistan in the deadliest single combat incident of the decade-long war.
Obama learned of the deaths while at Camp David. In a written statement, he says Americans' thoughts and prayers go out to the families of those who perished. He also mourned the loss of seven Afghan soldiers killed in the crash.