U.S. officials say the Navy SEALs and other troops lost in Saturday's helicopter crash in Afghanistan had rushed to the area to help fellow U.S. troops under fire.
The officials say the SEALs had responded to a request by U.S. Army Rangers who were taking heavy fire after going after a target.
One of the officials says the SEALs had completed their mission, subduing the attackers, and were departing in a U.S. Army Chinook helicopter when it was apparently hit by rocket-propelled grenade fire.
The other official said that the Rangers, special operations forces who work regularly with the SEALs, secured the crash site afterward. Both officials spoke on condition of anonymity to describe the event while the investigation remains ongoing.
The SEAL mission was first reported by CNN.