Captain Brett Crozier, commanding officer of the U.S. Navy aircraft carrier USS Theodore Roosevelt, addresses the crew during an all-hands call on the ship's flight deck in the eastern Pacific Ocean December 19, 2019.

WASHINGTON — An aircraft carrier captain who made a stunning plea for help over a coronavirus outbreak on his vessel has been relieved of duty.

The officer, Capt. Brett Crozier of the USS Theodore Roosevelt, had written a letter to military leadership regarding the situation on his carrier, and it leaked to the media.

"The captain's actions made his sailors, their families, and many in the public believe that his letter was the only reason help from our larger Navy family was forthcoming, which was hardly the case," Thomas Modly, acting Secretary of the Navy, told reporters Thursday at the Pentagon.

"It raised alarm bells unnecessarily," he added, saying that the Navy was making preparations to address the concerns laid out in the letter. Modly said that the captain's letter, dated March 30, was sent via nonsecure unclassified email and also outside the chain of command.

In a four-page letter, first reported by the San Francisco Chronicle, Crozier described a worsening coronavirus outbreak aboard the warship, a temporary home to more than 4,000 crew members. More than 100 people on the ship were infected.

"We are not at war. Sailors do not need to die. If we do not act now, we are failing to properly take care of our most trusted asset — our Sailors," Crozier wrote. "The spread of the disease is ongoing and accelerating."