By Patricia Weiss and Ludwig Burger

FRANKFURT (Reuters) - Bayer has told U.S. lawmakers it could stop selling the popular Roundup weedkiller unless they can strengthen legal protection against product liability litigation, according to a financial analyst and a person close to the matter.

Bayer has paid about $10 billion to settle disputed claims that Roundup, based on the glyphosate herbicide, causes cancer. About 67,000 further cases are pending for which the group has set aside $5.9 billion in legal provisions.

The German company has said plaintiffs should not be able to take Bayer to court invoking U.S. state rules given the federal U.S. Environmental Protection Agency has repeatedly labelled the product as safe to use, as have regulators in other parts of the world.

"Without regulatory clarity (Bayer) will need to exit the business. Bayer have been clear with legislators and farmer groups on this," analysts at brokerage Jefferies said in a note on Thursday, citing guidance Bayer's leadership provided in a meeting.

Bayer, which acquired Roundup under the $63 billion takeover of Monsanto in 2018, said: "We are exploring every possibility to end this litigation." It declined to comment further.

Disclosing glyphosate sales numbers for the first time, Bayer on Wednesday said the product, one of the most widely used weedkillers in U.S. field farming, generated 2.6 billion euros ($2.8 billion) in revenue last year.

"Bayer could reach a point in the future where the company is forced to discontinue the sale of the product in the United States," a person familiar with the matter told Reuters, requesting anonmyity because of the sensitivity of the matter.

As it released fourth-quarter earnings on Wednesday, the company said it was working to "significantly contain" litigation by 2026.

It has repeatedly said it is working with farmers' associations to lobby U.S. federal and state legislators. It is also preparing to again petition the Supreme Court for legal protection, following a failed attempt in 2022.

Bayer, however, has not previously threatened to withdraw the product from the U.S. market, although it replaced glyphosate in U.S. consumer products with different weed-killing substances.

(Editing by Gerry Doyle and Barbara Lewis)