(AP) — The world headquarters of agriculture company Monsanto was the site of a weekend demonstration organized by opponents of genetically modified food.

500 demonstrators marched Saturday to the company’s Creve Coeur global headquarters, where they chanted anti-Monsanto slogans and waded into street traffic.

Organizers of the “March Against Monsanto” want the company to label food containing genetically modified ingredients.

Monsanto released a statement before the protest that highlighted what the company calls its contribution to improving agriculture by helping farmers produce more from their land while conserving natural resources.