(Reuters) -McDonald’s Corp on Sunday said Carl Icahn has nominated two members to its board of directors in an escalating fight over the treatment of pigs by the burger chain’s suppliers.

The billionaire activist investor, who stated that he holds 200 shares in the company, nominated Leslie Samuelrich and Maisie Ganzler to stand for election at the 2022 annual meeting, the company said in a statement, adding that it would evaluate the nominees as it would any other board candidates.

Icahn has previously said that it is “obscene” how the animals used for McDonald’s products are treated.

Icahn has insisted on new McDonald’s commitments, including requiring all of the company’s U.S. pork suppliers to move to “crate free” pork, and set specific timeframes, the company said.

Such a commitment would be impossible given the current supply “and would harm the company’s shared pursuit of providing customers with high quality products at accessible prices,” the statement said.

McDonald’s pledged in 2012 to source pork from producers who do not use small crates to house pregnant sows. Icahn pushed for the change behind the scenes, the Wall Street Journal reported earlier this month.

“Since making this commitment, McDonald’s has led the industry, and today an estimated 30%-35% of U.S. pork production has moved to group housing systems,” the company’s statement said.

The company expects to source 85% to 90% of its U.S. pork volumes from sows not housed in gestation crates during pregnancy by the end of 2022 and expects 100% of its U.S. pork to come from sows housed in groups during pregnancy by the end of 2024, it added.

McDonald’s also said it was “noteworthy” that Icahn, the majority owner of Viskase, a company that supplies packaging for the pork industry, “has not publicly called on Viskase to adopt commitments similar to those of McDonald’s 2012 commitment.” Icahn did not immediately respond to a request for comment.

McDonald’s said it sources only approximately 1% of its U.S. pork production and does not own any sows, or produce or package pork in the United States.

Icahn, who became known as a corporate raider on Wall Street, was embroiled in a proxy battle with Southwest Gas Holdings Inc in November last year.

(Reporting by Anirudh Saligrama in Bengaluru; additional reporting by Andrew Chung and Svea Herbst-Bayliss; Editing by Lisa Shumaker and Mark Porter)