Vehicle-maker AM General has won a $428.3 million contract to provide the U.S. Army with Humvee ambulance chassis vehicles.

The award is an indefinite-delivery/indefinite-quantity, firm-fixed-price contract for a period of six years.

AM General said that under the initial award, 654 of the M997A3 vehicles will be provided to the Army National Guard. The Army and Army Reserve will also receive the ambulance chassis vehicles for use in domestic disaster relief operations.

"We are pleased to continue to support the active and future use of the more than 160,000 HMMWV's currently in service as part of U.S. Army, Marine Corps, Reserves and National Guard fleets," said Chris Vanslager, AM General vice president, Programs and Business Development.

"This contract is yet another example of the ongoing critical operational need for the HMMWV and how AM General remains the unmatched leader in modernizing and maintaining the HMMWV fleet in the United States and around the world.

"No company has more light tactical vehicle experience than AM General, and we look forward to working with our valued customers to leverage our five decades of expertise in the design, engineering and manufacturing of this iconic vehicle which will be in the service of U.S. military fleets through 2050."

The contract win follows last month's loss of a major Army contract for eventual production of more than 50,000 Joint Light Tactical Vehicles, which will eventually replace part of the military's Humvee utility vehicles.

The JLTV award carried a total value of more than $6 billion if all options were exercised. The low-rate initial production award given by the Army to Oshkosh Defense carried a value of $114.7 million. A full-rate production award is expected in fiscal year 2018, with production running through 2040.

AM General said it has no intention of protesting the award to Oshkosh Defense and will concentrate on contracts at hand.

"... We believe a protest would ultimately result in a distraction from our current growth business areas, including meeting the significant current and future needs of our customers in the United States and around the globe.

"Specifically, with approximately 230,000 HMMWVs currently serving as integral tactical vehicles of fleets around the world, AM General has a critical role in ensuring these vehicles remain mission ready and as capable as possible, to include the most innovative survivability and communications capability available only from AM General, now and into the future."

Lockheed Martin, another competitor for the JLTV contract, is protesting its loss.

"Lockheed Martin does not take protests lightly, but we are protesting to address our concerns regarding the evaluation of Lockheed Martin's offer," the company said in a statement.