The respected head of the aircraft carrier, hit by the fast-moving coronavirus pandemic, was removed from his command by Acting Navy Secretary Thomas Modly Thursday after a letter Crozier wrote pleading with the Pentagon for support for the crew was leaked into the public.

Crozier "demonstrated extremely poor judgment in the middle of a crisis" in his handling of the letter, Modly said.

But the crew of the Roosevelt openly signalled their support in videos taken from the ship as he strode alone solemnly down the gangway, saluting briefly to the crew before getting into a waiting car on the pier.

"Captain Crozier, Captain Crozier," sailors on the deck of the warship chanted as they clapped.

"That's how you send out one of the greatest captains you ever had," an identified person can be heard saying on one of the videos posted on social media.

Crozier's dismissal came as the Pentagon struggles to maintain the readiness of its air, sea and ground forces around the world as the COVID-19 virus sweeps the globe, all the while providing domestic US support to government efforts to contain the virus and treat the infected.

With dozens on its sailors infected after a five-day official visit to Vietnam, the Roosevelt sailed into the US naval base at Guam in the western Pacific on March 28.

On Tuesday, a letter that Crozier wrote to his superiors pleading to vacate as much of the ship as possible and put most of its 4,800 sailors in quarantine on land was leaked to US newspapers, angering the Pentagon leadership.

"The spread of the disease is ongoing and accelerating," he wrote. "We are not at war. Sailors do not need to die," he pleaded.

Pentagon officials said they were doing just that, and bristled at the fact that Crozier distributed the unclassified letter widely, almost ensuring it would leak out.

Modly said the letter misrepresented how the Navy was dealing with the ship and caused unnecessary panic.

In addition to frightening families of the sailors, he said, "it raised concerns about the operational capabilities and operational security of that ship that could have emboldened our adversaries to seek advantage."

Pentagon officials stressed that it was the handling of communications by Crozier, and not his specific sentiments, that sparked the rare removal of a ship's captain.

But some also blamed Crozier for taking the risk of having the Roosevelt visit Vietnam's Danang harbor for five days in early March, although that important diplomatic stopover would have been approved much higher up in the Pentagon, where the coronavirus had already sparked concerns about it potential impact on US forces.