Berlin (AFP) - US seeds and pesticides maker Monsanto kept lists of around 600 key pro- and anti-pesticides figures in Germany and France alone, its German parent company Bayer said Monday amid a widening probe.

Bayer has admitted the lists covered politicians, journalists and others across seven European countries and in Brussels.

"Update on Monsanto stakeholder lists: until the end of last week, the firm hired by Bayer contacted all the people on the German and French lists," Bayer's press department tweeted. "There are a total of around 600."

Bayer said last month that PR agency FleishmanHillard drew up lists of stakeholders in France, Germany, Italy, Netherlands, Poland, Spain and United Kingdom, "as well as regarding stakeholders related to EU institutions".

The group had promised transparency over the lists, after a French television channel revealed the existence in France of files on prominent backers and opponents of pesticides and genetically modified crops.

AFP has filed a complaint with a French data protection regulatory body because some of its journalists were on the list.

Bayer hired law firm Sidley Austin to investigate the lists and to determine whether they extended to other countries.

Sidley Austin is contacting the individuals named to inform them what data FleishmanHillard collected on them.

The Leverkusen-based group has said it would suspend the agency's PR work.

Bayer's admission adds to the company's woes that have piled up since it acquired Monsanto for $63 billion in 2018 -- one of the largest in German corporate history -- which has also lumbered it with a massive burden of health-related lawsuits.

The lists in question date back to 2016, before Bayer took over Monsanto.