WASHINGTON -- The Pentagon said Monday it will not allow media to document the return to the United States of the bodies of 22 Navy SEALs and eight other service members because the remains are unidentifiable and therefore families can't grant permission for access.

The bodies were expected to arrive at Dover Air Force Base in Delaware on Tuesday following the weekend helicopter crash in Afghanistan. Military officials say a rocket-propelled grenade took the Chinook down. It was the deadliest incident for American forces in the decade-long war. Twenty-two elite Navy SEAL personnel, Air Force troops and an Army air crew, along with eight Afghan soldiers

"Because the remains are unidentified at this point, next-of-kin are not in a position to grant approval for media access to the dignified transfer. Therefore, in accordance with DoD policy, no media coverage of the arrival and dignified transfer is permitted. Families will however, be given the opportunity to be present for the arrival," Capt. Jane Campbell, a Pentagon spokeswoman, said.

Campbell add that the bodies will be positively identified by the Armed Forces Mortuary Affairs Office at Dover.

In 2008 former Defense Secretary Robert Gates helped lift a Bush-era ban on media access at Dover that prevented the public from seeing images of fallen troops returning home. Until then, the ban had been widely criticized for being politically motivated with the intent to cover up the so-called "cost of war."

Since then, permissions have been routinely sent out for coverage. This time, members of the press are requesting an exception in this case so that photographers are allowed to cover the arrival ceremony.

The crash has taken a heavy toll on military families and their supporters, and President Obama said Monday that the deaths present "a time to reflect on those we lost and the sacrifices of all who serve, as well as their families."

"These men and women put their lives on the line for the values that bind us together as a nation. They come from different places, and their backgrounds and beliefs reflect the rich diversity of America. But no matter what differences they might have as individuals, they serve this nation as a team," Obama said of armed forces.

Obama also vowed to "press on" and said the U.S. will succeed there, adding that the troops are working hard to transition to a stronger Afghan government and ensuring that Afghanistan is not a safe haven for terrorists.