WASHINGTON — A mutiny has erupted among photographers who cover President Obama over what they say is the White House’s increasing practice of excluding them from events involving the president and then releasing its own photos or video.

On Thursday, the White House Correspondents’ Association and 37 news organizations submitted a letter to the press secretary, Jay Carney, protesting what photographers said amounted to the establishment of the White House’s own Soviet-style news service, which gets privileged access to Mr. Obama at the expense of journalists who cover the president.

“As surely as if they were placing a hand over a journalist’s camera lens,” the three-page letter said, “officials in this administration are blocking the public from having an independent view of important functions of the executive branch of government.”