Kittery, Maine — The Groton-based USS Miami nuclear-powered attack submarine caught fire at the Portsmouth Naval Shipyard late Wednesday afternoon.

Seven people were injured in the fire, including five firefighters.

Crews responded at about 5:40 p.m. Wednesday to the USS Miami SSN 755 at the Portsmouth Naval Shipyard on an island in Kittery, a town near Portsmouth, N.H. It was not clear how many people were aboard the submarine at the time.

Rear Adm. Richard Breckenridge, commander of Submarine Group Two, said the fire was out Thursday morning and the shipyard was open as usual. He said the three shipyard firefighters, two civilian firefighters and two crew members received minor injuries and were in good shape.

The submarine's reactor was not operating when the fire started and was not affected by the blaze, shipyard spokeswoman Bridget Church said.

Federal authorities were alerted to the situation, Church said.

Kittery Police Chief Paul Callaghan said his department had not received any requests from the shipyard to evacuate the area. He said the fire aboard the USS Miami was not posing a danger to the general public.

Callaghan said Kittery firefighters are on standby at the shipyard's fire station.

The crew of 13 officers and 120 enlisted personnel brought USS Miami (SSN 755) to the shipyard on March 1 to undergo maintenance work and system upgrades.

The submarine's commanding officer is Commander Roger E. Meyer, who assumed command on Sept. 20, 2010.

The Miami was launched at Electric Boat in November 1988 and commissioned at the Naval Submarine Base in New London on June 30, 1990. About 1,200 attended the commissioning, including guest speaker U.S. Rep. Ileana Ros-Lehtinen, R-Fla.

Miami's 1988 launch was three-and-half-month's behind schedule because of a 103-day strike by EB's 10,000 unionized shipbuilders.

The USS Miami is the 26th Los-Angeles class submarine delivered by Electric Boat and the 44th ship of that class to be commissioned. The 6,900-ton, 260-foot-long Miami carries an armament of Tomahawk cruise missiles and Harpoon anti-ship missiles and cost about $600 million to build.

It was the fifth of the "improved" Los Angeles-class subs, with a hardened sail for Arctic surfacing, a more sophisticated computer system and retractable bow planes.

The submarine was first commanded by Cmdr. Thomas W. Mader of Gales Ferry, with a crew of 120 and 13 officers.

It is the first submarine and the third U.S. Navy ship to bear the name Miami. The first was a side-wheel, double-ended wood gunboat launched at the Philadelphia Navy Yard in 1861.

The second was a light cruiser launched in Philadelphia by Cramp Shipbuilding Co. in 1942. During World War II, the cruiser Miami served in the Pacific and helped support the Marianas campaign. Several members of that crew were in the audience on June 30, 1990, for the submarine's commissioning.

Tom Clancy's non-fiction book, "Submarine: A guided tour inside a Nuclear warship," published in 1993, was based on the USS Miami. A crew member in September 1994 said the USS Miami was the first submarine to go through the Suez Canal.

An Associated Press report contributed to this story.