SACO — Defense contractor General Dynamics is laying off more than 100 workers at its gun manufacturing plant in Saco.

Spokesman Karl Johnson says 110 workers representing nearly a third of the plant’s workforce have been notified that they’ll be let go between June 14 and July 1. He says 100 of the laid-off employees are hourly workers.

Johnson says the layoffs are necessary because of a sharp reduction in the Army’s demand for heavy machine guns and grenade launchers, brought on by the drawdown in U.S. forces in Iraq and Afghanistan.