A U.S. nuclear-powered attack submarine struck an object while submerged in international waters in the Indo-Pacific region last week, the Navy said, adding that no life-threatening injuries were reported.

"The submarine remains in a safe and stable condition. USS Connecticut’s nuclear propulsion plant and spaces were not affected and remain fully operational,” U.S. Pacific Fleet said in a statement late Thursday, adding that the extent of the damage from the Oct. 2 incident is being assessed.

A U.S. Naval Institute News report, citing an unnamed defense official, said 11 sailors suffered minor to moderate injuries when the submarine hit an unknown underwater object in the South China Sea. The last known incidence of a U.S. submarine striking an underwater object took place in 2005, when the USS San Francisco struck an underwater mountain in a collision that killed one sailor aboard, it said.