The USS Connecticut, a nuclear-powered fast-attack submarine, "struck an object while submerged on the afternoon of Oct. 2, while operating in international waters in the Indo-Pacific region," the navy said in a statement.

It said there were no life-threatening injuries, but USNI News, a site specializing in navy news, reported that about a dozen sailors were hurt "with moderate to minor injuries."

USNI News also said the submarine was operating in the South China Sea, where the US Navy has sought to challenge China's disputed territorial claims on small islands, reefs and outcrops.

The navy said the extent of the damage is being examined and the incident investigated.

"The submarine remains in a safe and stable condition. USS Connecticut's nuclear propulsion plant and spaces were not affected and remain fully operational," it said.

USNI News said the vessel is now headed to the US base at Guam.