(Reuters) -A group founded by former Trump administration officials accused Tyson Foods ( TSN ) on Wednesday of discriminating against U.S. citizens by disproportionately hiring immigrants, including children and people in the country illegally.

America First Legal (AFL) sent letters to the U.S. Department of Justice, the Equal Employment Opportunity Commission, and an Iowa civil rights agency calling for investigations into the Arkansas-based meatpacker's employment practices.

The letters say that Tyson employs 42,000 foreign workers, making up more than one-third of its U.S. workforce, and is involved in programs to recruit more.

More than half of all meatpacking workers in the U.S. are immigrants, compared with about 17% of the entire U.S. workforce, according to the Center for Economic and Policy Research, a think tank.

AFL said Tyson has taken advantage of a sharp increase in illegal border crossings that peaked last year in order to build a pool of cheap labor.

The group is headed by Stephen Miller, who was a senior adviser to Republican former President Donald Trump known for his hardline stance on immigration. Former Acting U.S. Attorney General Matthew Whitaker is a board member for the group, and some of the group's staff lawyers worked at the Trump-era Justice Department.

AFL noted that a major food sanitation company that contracts with Tyson and other meat processors recently paid $1.5 million in penalties for employing teenagers in dangerous jobs. Some of those children worked at Tyson plants, though the company was not accused of wrongdoing.

AFL accused Tyson of violating federal and Iowa laws barring employers from discriminating based on citizenship status, race, national origin and other traits.

A Tyson spokesperson in a statement said the company is strongly opposed to illegal immigration and does not allow the employment of anyone under the age of 18 in its facilities.

"Any insinuation that we would discriminate against Americans to hire immigrant workers is completely false. Today Tyson Foods ( TSN ) employs 120,000 team members in the United States, all of whom are required to be legally authorized to work in this country," the spokesperson said.

The Justice Department, the EEOC and the Iowa agency are not obligated to respond to the complaints or investigate them. If they conduct probes and find merit to the claims, they could attempt to broker a settlement with Tyson or sue the company.

AFL has filed more than 30 complaints, mostly with the EEOC, accusing major U.S. companies of adopting diversity policies that discriminate against men or white, Asian and heterosexual workers. But the complaint against Tyson appears to be the first by the group to involve claims of bias against American workers.

The commission has not said whether it is investigating any of the complaints.