KITTERY, Maine - A fire has been reported on a nuclear submarine at the Portsmouth Naval Shipyard. The Portsmouth Fire Department is responding to the fire on the USS Miami SSN 755. Shipyard public affairs specialist Gary Hildreth says the fire is located in the forward compartment of the ship. He says emergency personnel are on the scene. All nonessential personnel have been evacuated from the ship.

A fire on a nuclear-powered submarine at a Maine shipyard has injured four people.

Fire crews responded Wednesday to the USS Miami SSN 755 at the Portsmouth Naval Shipyard on an island in Kittery, a town near Portsmouth, N.H., popular with tourists.

The shipyard says four injured people have been treated and released. The Portsmouth Herald newspaper says firefighters were injured.

Shipyard public affairs specialist Gary Hildreth says the fire started in the forward compartment of the sub. The shipyard says the sub's reactor wasn't operating at the time and was unaffected. The cause of the fire hasn't been identified.

Nonessential personnel were removed from the sub. Black smoke billowed overhead.

The USS Miami arrived at the shipyard for maintenance and upgrade work in March. Its home station is Groton, Conn., where the U.S. Navy has a base.