Only some of those infected onboard the ship, the U.S.S. Milwaukee, were experiencing mild symptoms, said Commander Kate Meadows, a Navy spokeswoman. It was not clear how many infections involved the Omicron variant, which continues to gain dominance rapidly around the world.

The crew held an open-air Christmas service on the pier on Saturday, which allowed the sailors to remain socially distanced and to follow public health guidelines, according to Commander Meadows.

“They are using the open space and fresh air for as many safe activities as they can,” she said. “The chefs onboard are making a special Christmas meal today for everyone.”