Updated 5:09 p.m.
Argentina's tax agency has accused a Monsanto contractor of what it calls slave-like conditions among workers in its cornfields.
The Federal Administration of Public Revenues (AFIP) says Rural Power SA hired all its farmhands illegally, restricted them from leaving the building where they were housed, and withheld their salaries.
The 65 workers had to de-tassel corn 14 hours a day and buy their food at inflated prices from the company store.
In December, Argentina's Congress passed a law providing farm workers with a number of protections, including an eight-hour work day.
AFIP says it will hold Monsanto responsible for its contractor's illegal labor practices.
In an e-mail, Monsanto spokesman Thomas Helscher said the following:
"We have not yet received any details about AFIP’s claims beyond the brief communication they issued yesterday afternoon. Monsanto places the highest priority on the safety and welfare of our contractors and employees, and we believe that our contractors in Argentina were complying with all applicable requirements. When details of the AFIP charges are available to us, we will certainly investigate the matter promptly."