President Obama participates in a ceremony at Dover Air Force Base in Dover, Del., for the transfer of U.S. and Afghan personnel who died in Afghanistan on Aug. 6. (Pete Souza/THE WHITE HOUSE)

This post has been updated.

President Obama’s trip to Dover Air Force Base in Delaware on Tuesday to pay respects to 30 fallen U.S. servicemen was a historically poignant and symbolic moment for his presidency and the decade-old Afghanistan war.

Yet members of the White House press corps were instructed not to report on the trip ahead of time and then kept away from the “dignified transfer” ceremony of the troops’ remains once they arrived at Dover.

Instead, a group of about 15 reporters known as the “traveling press pool” was allowed to watch the president’s Marine One helicopter land at Dover. They were then herded into an auditorium at the base and kept there for five hours, forced to rely on intermittent briefings from White House officials who accompanied Obama to meetings with family members and the somber transfer ceremony at the airplane hangar where the bodies were delivered.

White House officials stressed that they were following decisions made by the Secret Service and military based on those agencies’ policies.

But the decisions left the pool reporters frustrated, and many in the larger White House press corps back in Washington fuming. Some wondered whether the administration was trying to whitewash the event and prevent detailed accounts of the anguish of the 250 family members who were on hand to accept the remains of the largest number of U.S. troops killed in Afghanistan in a single day.

Asked during his daily briefing Wednesday why the president’s trip to Dover was kept secret, White House spokesman Jay Carney said the Secret Service made the decision based on security considerations.

“That’s a good question,” Carney said. “I can tell you that’s something we were advised to do. I refer you to the Secret Service.”

The White House had also cited security when it notified the travel pool of the trip late Tuesday and demanded that the the trip not be reported until Obama arrived at Dover. (The White House invites the rotating group of travel reporters on trips where a larger media scrum cannot be accommodated because of security or infrastructure issues. The Washington Post took part in the Dover trip as part of its position in the randomly assigned traveling pool rotation.)

Carney was also asked why reporters and photographers were unable to view the dignified transfer ceremony at Dover. Normally, the military gives families the option of allowing reporters into the event, and many families choose to allow it.

In this case, however, the families were not given that option, Carney said. The reason was that the service members, who were killed on Saturday along with eight Afghan allied troops when their Chinook helicopter crashed during a mission, had not yet been positively identified. A Dover official said the crash was so horrific that the bodies would require DNA, dental and fingerprint examinations to make positive identifications.

(The Pentagon knows the names of those who were killed and recently announced it will make the list public. )

Josh Earnest, one of Carney’s deputies, stressed that the decision was made by the military based on Defense Department protocol. Because the remains had not been positively identified, some were potentially commingled in the transfer containers and, therefore, an individual family could not request media presence while a particular container was being transferred.

“There are a variety of reasons why the press was not allowed to cover the dignified transfer of remains,” Carney said. “Normally families have to give permission, but because of the state of the remains, the policy was that the press would not be allowed.”

The White House did release its own photograph of the president during the ceremony — he is backlit while saluting — taken by official White House photographer Pete Souza.

“The reason we were able to release a photo is because it was carefully done so that none of the transfer cases that contained remains were in the picture,” Carney said.

Stressing that the president was not trying to hide the trip because of the high number of troop losses, he added: “The president was very proud to go. On Marine One flying back, someone on the helicopter, someone who is in military service, thanked the president for making the trip. He looked up and said, ‘It’s my honor to talk to those families,’ and said he could think of nothing better.”