The Pentagon said Monday that it will prohibit news coverage of the return to the United States of 30 American troops who were killed in a helicopter crash on the deadliest day of the decade-long Afghanistan war.

The somber military ritual at Dover Air Force Base of honoring the fallen as they return home was reopened to the public in March 2009 after an 18-year ban. Coverage of the return of troops’ remains — termed “dignified transfers” by the military — has been permitted since then as long as relatives of the deceased approve.

But Pentagon officials said that the catastrophic nature of Saturday’s crash made it impossible to preliminarily identify any of the service members. As a result, they said, family members won’t have the option to grant permission for news coverage at Dover.

Marine Col. David Lapan, a Pentagon spokesman, said the decision was not an attempt to restrict public images of war. He said Defense Department officials agreed over the weekend “that if there were any identifiable remains in the group . . . and the family said yes, we’d allow media coverage.”

“The instance that we have here are unidentifiable remains,” he added.

Lapan said flag-draped cases bearing the remains of the 30 troops — 22 Navy SEALs, three Air Force Special Operations airmen and five Army aviators — are scheduled to arrive at Dover on Tuesday.

As of Monday afternoon, the Pentagon had not released the names of the fallen troops, although many had been revealed by relatives to reporters. Lapan said all will be officially identified at the same time after their next of kin are notified.