In this Sept. 29, 2017, file photo, Bath Iron Works President Dirk Lesko leaves a news conference during a visit by Navy Secretary Richard Spencer, right, in Bath. Credit: Robert F. Bukaty / AP

There has been an unexpected shake-up at one of the state’s biggest employers.

Dirk Lesko, who until Thursday was the president of Bath Iron Works, has resigned, effective immediately, according to a memo that went out to employees.

Lesko was named president of the shipyard in 2016.

General Dynamics, the parent company of the Bath shipyard, isn’t saying much about his resignation.

Robert E. Smith is running the shipyard until a permanent replacement is found.