(Reuters) -- Agricultural processor Archer Daniels Midland Co on Tuesday said it will eliminate 20 percent more jobs than previously expected to reduce costs.

The Decatur, Illinois-based company raised its cutback estimate to more than 1,200 jobs worldwide, up from an earlier target of about 1,000 jobs. The increased estimate includes recent layoffs at grain and soy processing plants in the United States, spokesman David Weintraub said.

ADM announced in January that it would make the first broad staffing reduction in the company's history to become more competitive.

Agricultural companies have come under pressure from volatile global markets and poor margins for soy crushing, with rival agricultural giant Cargill also making cut jobs to save money.

ADM is reducing its headcount through early retirement incentives and layoffs. The window for taking early retirement has now closed, and the company will notify U.S. employees this week that their jobs are being cut, Weintraub said.

ADM has already reduced its workforce in Decatur by 7 percent, with 160 employees taking early retirement and 175 being laid off, Weintraub said.

Overall, about 420 employees accepted the early retirement incentive and will leave the company during the next year, Weintraub said. He would not say how that number fit into the company's expectations.

We're not going to handicap that, he said.

Job cuts will mostly hit employees in corporate functions, including human resources, IT and communications, as opposed to those working in processing plants, Weintraub said.

Among the facilities being closed is an ethanol plant with 61 employees in Walhalla, North Dakota.

(Reporting By Tom Polansek; Editing by Lisa Shumaker)