SAO PAULO (Reuters) - U.S. grains merchant Archer-Daniels-Midland ( ADM ) is making a fresh wave of job cuts this week at its largest unit, the grain trading and oilseed processing division, according to three sources briefed on the matter.

Chicago-based ADM said in February it would cut up to 700 jobs and reduce costs by $500 million to $750 million over the next three to five years, after posting its lowest fourth-quarter adjusted profit in six years. The job cuts would represent about 1.7% of the company's global workforce.

It was not immediately clear if the latest layoffs are part of that announcement or are additional staffing reductions. ADM did not respond to a request for comment.

Reuters could not confirm the number of job cuts this week. 

The new wave of cuts began at ADM's Swiss office, which is its European headquarters, one source said, speaking on condition of anonymity.

The cuts would be disruptive to ADM's agricultural services and oilseeds business, said another source, as employees, including experienced traders, worried over who might be targeted next. That unit, ADM's largest, houses the company's global crop trading, transportation and storage, and oilseed processing operations.

The division appeared to be the focus for this round of cuts, rather than ADM's nutrition unit, one of the sources added.

Each region where ADM operates was given specific cost-cutting targets by Chief Financial Officer Monish Patolawala, according to one of the sources. 

ADM tapped Patolawala for the job last July as it dealt with multiple U.S. investigations, including a criminal one, related to accounting irregularities.

(Reporting by Ana Mano in Sao Paulo and Chris Prentice in New York; Additional reporting by Karl Plume in Chicago; Editing by Emily Schmall and Rod Nickel)