The U.S. Navy has awarded General Dynamics Electric Boat a $102.8 million contract modification to develop Virginia-class attack submarines.

Under the contract, General Dynamics subsidiary Electric Boat will provide research, development and lead-yard services for the submarines, as well as evaluate the new technology being used to produce the vessels. The contract modification brings the cumulative value of the company's contract with the U.S. Navy to $1.1 billion.

Attack submarines are designed to engage both enemy submarines and surface ships. They are equipped with Tomahawk cruise missiles and K48 ADCAP torpedoes, reach speeds over 25 knots, and have a length of 34 feet.

Virginia-class submarines are also fitted for intelligence, surveillance, and reconnaissance operations, in addition to mine warfare. Virginia-class vessels are one of three classes of attack submarines in service in the U.S. Navy, which also includes the Los Angeles class and the Seawolf class.