A U.S. fast-attack submarine struck an object while submerged in international waters in the Indo-Pacific region, the Navy said Thursday. It said there were no life-threatening injuries and the sub was fully operational.

In a brief statement providing few details of an incident that happened five days ago, U.S. Pacific Fleet said the USS Connecticut remained in a “safe and stable condition.” The Seawolf-class submarine's nuclear propulsion plant was not affected, it added.

“The extent of damage to the remainder of the submarine is being assessed,” the statement said, adding that the incident will be investigated. It did not cite a specific location for the collision or the current position of the sub.