WASHINGTON - U.S. officials tell The Associated Press that they believe that none of the Navy SEALs who died in a helicopter crash in Afghanistan had participated in the raid that killed Osama bin Laden, although they were from the same unit that carried out the bin Laden mission.

Sources say that more than 20 Navy SEALs were among those lost in the crash in Afghanistan.

The operators from SEAL Team Six were flown by a regular Army crew. That's according to AP military sources.

Another source says the team was thought to include 22 SEALs, three Air Force air controllers, seven Afghan Army troops, a dog and his handler, and a civilian interpreter, plus the helicopter crew.

The sources thought this was the largest single loss of life ever for SEAL Team Six, known as the Naval Special Warfare Development Group.

All sources spoke on condition of anonymity to discuss sensitive military matters.