Health campaigners have written to U.S. regulators accusing Philip Morris International (PM.N), opens new tab of misrepresenting past regulatory decisions, seeking to disrupt the launch of its flagship heated tobacco device IQOS in the United States.

The world's biggest tobacco company by market value has spent billions of dollars developing the product, which investors see as key to driving future growth. But it needs permission from the U.S. Food and Drug Administration to sell it in the world's second largest tobacco market by revenue.

Six anti-tobacco and health groups, including the Campaign for Tobacco-Free Kids, the American Academy of Pediatrics and the American Lung Association, wrote to the FDA to oppose IQOS-related applications PMI has submitted to the agency.

"PMI has repeatedly made misleading and deceptive statements wrongly suggesting that the FDA has found that IQOS reduces the risk of disease," the letter, opens new tab, dated June 27 and reviewed by Reuters, said.

The campaign groups allege that PMI violated the FDA's orders by suggesting IQOS offered lower risks than cigarettes. Their letter cited four examples of such statements in the United States, the Philippines, Mexico and Kazakhstan.

They also said in the letter that upcoming independent studies contradict PMI's findings about how many