WASHINGTON (Reuters) - The U.S. Navy has informed lawmakers of its intent to pursue a block purchase of two Ford-class aircraft carriers, Senator Tim Kaine’s office said on Monday, a step officials have said could save billions of dollars as the Trump administration tries to expand the size of the fleet.

The decision comes nine months after the Navy expressed interest in a block buy and asked shipbuilder Huntington Ingalls Industries for detailed pricing on the cost of two aircraft carriers as it considered doubling its order for the most expensive ship in the U.S. fleet in a bid to save money.

The Navy commissioned the first Ford-class aircraft carrier, the USS Gerald R. Ford, in July 2017, three years behind schedule and billions of dollars over budget. The Ford cost about $13 billion.

The Navy has said it would spend about $43 billion in total to build the first three ships in the Ford class. Huntington Ingalls Chief Executive Mike Petters has said multi-ship purchases are the best way to reduce costs.

Kaine, of Virginia and a member of the Senate Armed Services Committee, said a block buy would save billions and provide more stability to the Hampton Roads shipbuilding community in southeastern Virginia.

“This smart move will save taxpayer dollars and help ensure the shipyards can maintain a skilled workforce to get the job done,” he said in a statement.

The Navy released a force structure goal in 2016 that calls for a 355-ship fleet. Previously it had a goal of 308 ships, and the actual size of the Navy had generally been between 270 and 290 ships, according to the Congressional Research Service.

A 355-ship fleet would include 12 aircraft carriers, one more than the previous goal. The United States currently operates 11 aircraft carriers, several times more than any other country.