“The extent of damage to the remainder of the submarine is being assessed,” the statement said, adding that the incident will be investigated.

The statement did not specify the location of the incident, but two US Navy officials, speaking on condition of anonymity to discuss details not announced publicly, said it happened in the South China Sea while the Connecticut was conducting routine operations.

The officials said the sub then headed toward port at Guam.

They said the incident was not announced before Thursday to maintain operational security.

The officials said it was not yet clear what object the sub had struck but that it was not another submarine.

One official said it could have been a sunken vessel, a sunken container or other uncharted object.

Two sailors aboard the Connecticut sustained moderate injuries and about nine others had minor injuries like scrapes and bruises, the officials said. All were treated aboard the sub.

Additional reporting by Agence France-Presse

“The extent of damage to the remainder of the submarine is being assessed,” the statement said, adding that the incident will be investigated.

The statement did not specify the location of the incident, but two US Navy officials, speaking on condition of anonymity to discuss details not announced publicly, said it happened in the South China Sea while the Connecticut was conducting routine operations.

The officials said the sub then headed toward port at Guam.

They said the incident was not announced before Thursday to maintain operational security.

The officials said it was not yet clear what object the sub had struck but that it was not another submarine.

One official said it could have been a sunken vessel, a sunken container or other uncharted object.

Two sailors aboard the Connecticut sustained moderate injuries and about nine others had minor injuries like scrapes and bruises, the officials said. All were treated aboard the sub.

Additional reporting by Agence France-Presse