The U.S. Marine Corps has extended a contract to General Dynamics Land Systems to continue development of a new amphibious combat vehicle, the company reports.

The extension is for five months and carries a monetary value of $7 million.

Work under the extension includes flexibility and modularity analysis of the vehicle requirements and concept refinement and experimentation planning.

General Dynamics Land Systems in 2012 and 2013 had funded its own internal testing to assess the performance of its hull design against the Marine Corps' mine blast requirements for the amphibious vehicle, providing an early assessment of the low-risk, mature and affordable ACV solution.

The Marines are to issue a request for proposals for new ACVs this year. The vehicles must be able to self-deploy from a ship at least 12 miles from shore and travel in water at a speed of at least 12 knots.