WASHINGTON (Reuters) - General Dynamics Corp's National Steel and Shipbuilding Co division is being awarded a $640 million contract for the detail design and construction of a T-AO 205 Class Fleet Replenishment Oiler, the Pentagon said on Thursday.

If funding is available, the contract would include five additional ships, it said. If all the ships are constructed, the total value of the contract would be $3.16 billion, the Pentagon said.

(Reporting by Eric Beech; Editing by Eric Walsh)