The alleged shooter, a male, was critically wounded in the shooting at the U.S. Naval Support Activity Bahrain base, said the Navy official, who was not authorized to release the information to the media and spoke on condition of anonymity.
The official did not say if the alleged shooter shot himself or if anyone else was involved, but the Navy said the shooting was not terror related and only involved U.S. military personnel.
The shootings took place around 5 a.m., the Navy said. Officials closed the base temporarily and reopened it about an hour later.
No other details were immediately available, and the Navy said it was not releasing the names of those involved until their families were notified.
"The incident is under investigation, and it would not be prudent to discuss details at this time," said Navy spokesman Lt. John Gay.
Bahrain, a tiny island nation on the Persian Gulf, is a U.S. ally and home to the U.S. Navy's 5th Fleet, which is responsible for an area of about 2.5 million square miles of water including the Persian Gulf, Arabian Sea, Red Sea, Gulf of Aden, Gulf of Oman and parts of the Indian Ocean.
About 3,600 personnel work on the U.S. Naval Support Activity Bahrain base, located just outside Bahrain's capital, Manama. The base supports U.S. naval ships in the region.