ROME — Fincantieri is to use all three of its U..S shipyards to build new FFG(X) frigates and will hire 600 more staff by year-end to handle the work, a company official said following the U.S. Navy’s order for a second vessel out of a potential 10 in total.

The $553.9 million contract for the second Constellation-class guided-missile frigate was awarded Thursday to Fincantieri Marinette Marine based in Marinette, Wisconsin. The shipyard has experience building Freedom-class littoral combat ships for the Navy.

As opposed to the LCS program, work on the new frigate will also take place at two other Great Lakes sites controlled by Italian parent firm Fincantieri: Sturgeon Bay yard Fincantieri Bay Shipbuilding, which focuses on commercial shipping, and Green Bay yard Fincantieri ACE Marine, which specializes in aluminum vessels for the U.S. Coast Guard.

“With this step forward, we will keep pace with the program by building some sections [of the frigates] at Sturgeon Bay and Green Bay,” said Dario Deste, president and CEO of Fincantieri Marine Group.

The Navy picked Fincantieri last year to deliver the first Constellation frigate with options for a further nine vessels in a deal potentially worth $5.5 billion to the Italian group.

The new ships will be based on Fincantieri’s FREMM frigate, which is already in service with the French, Italian and Moroccan navies.

Preparation will see a $200 million investment at Marinette, where a new building will allow indoor construction of the vessels, while plans are underway for the construction of the largest ship lift in the United States. Smaller LCS vessels are currently side launched at the yard.

The staff count at the three yards will rise from the current 2,400 to about 3,000 this calendar year, said Deste, who predicts options for further vessels will be exercised once a year and then twice a year from 2023 or 2024.

The firm is now working on the detailed design phase of building the first-in-class USS Constellation, with construction due to start at the end of this year followed by delivery in 2026.

The contract marks Fincantieri’s debut as a prime contractor on a major U.S. Navy program after it partnered with Lockheed Martin for the LCS program. Lockheed took the role as prime for that effort.

Fincantieri CEO Giuseppe Bono has advocated that shipyards should be primes on naval programs and noted that the firm’s concept for the Constellation program has the advantage of being based on an operational vessel.