The commander of the submarine group that includes the USS Miami said Thursday it is too early to tell whether the nuclear-powered attack submarine, which caught fire late Wednesday afternoon at a Maine shipyard, will sail again.

The Miami (SSN 755) burned for more than eight hours at the Portsmouth Naval Shipyard in Kittery, Maine.

Rear Adm. Richard Breckenridge, Submarine Group Two commander, said in a news conference Thursday outside the shipyard that it was premature to say whether the Groton-based Miami could be repaired. The cause of the fire is not yet known.

U.S. Rep. Chellie Pingree, D-Maine, told the Kennebec Journal Thursday afternoon that Navy officials won't be able to enter the fire-damaged portion of the Miami for a few days to determine whether the submarine is salvageable.

Breckenridge said the blaze was contained to forward compartment spaces that were difficult to access. Reports said about 100 firefighters fought the blaze and encountered intense heat and heavy smoke inside the small compartments.

Seven people were injured fighting the fire, but their injuries were reported as minor. The injured included three shipyard firefighters, two civilian firefighters and two crew members.

"I want to emphasize that the heroic actions of the firefighting teams averted what could have been a much more severe situation," Breckenridge said.

The Miami's nuclear reactor had been shut down for more than two months and remained in a safe and stable condition during the fire. There were no torpedoes on board.

The shipyard remained open for normal business Thursday, and the workforce reported to work as scheduled.

The Miami was launched at Electric Boat in November 1988 and was commissioned at the Naval Submarine Base in Groton on June 30, 1990.

In 2010, the Navy awarded Electric Boat a $10.2 million contract modification to perform maintenance and modernization work on the Miami, the 26th Los Angeles-class attack submarine delivered by the Groton shipyard.

The Miami is in the midst of a 20-month stay at the Portsmouth Naval Shipyard. The crew of 13 officers and 120 enlisted personnel brought the submarine to the shipyard on March 1 to undergo maintenance work and system upgrades.

Kristin Fletcher, chief information officer for General Dynamics, said Thursday that she was unaware of EB workers heading to Kittery to help with the submarine's recovery phase.

Associated Press and Kennebec Journal reports contributed to this story.

jeff.johnson@theday.com