LONDON, May 2 (Reuters) - Philip Morris International PM.N said on Friday it will launch its IQOS heated tobacco device in Fort Lauderdale, Florida, the second U.S. city targeted by the cigarette maker in its tentative steps towards a national roll out.

PMI began selling IQOS, at the core of its efforts to diversify revenue away from cigarette brands like Marlboro, in Austin, Texas, in March. That kicked off efforts by the world's largest tobacco company to build a market for the device in the United States.

It hopes to ultimately capture a 10% share of U.S. tobacco and heated tobacco unit volume by 2030 and build a substantial base of new users in the world's top market for smoking alternatives. But a national launch is not planned until regulators authorise a newer version of the device for U.S. sale.

Until then, PMI said it would launch in four cities across two states. But until Friday, only Austin had been announced.

"The Fort Lauderdale region offers a dynamic blend of culture and industry, and we're thrilled to introduce IQOS to this community," said Stacey Kennedy, U.S. CEO, PMI.

The U.S. Food and Drug Administration is currently weighing PMI's application to sell the latest version of IQOS. The agency has already authorised PMI to sell the older device and market it as reducing exposure to harmful chemicals versus cigarettes.

Campaign groups like tobacco industry watchdog STOP, however, argue there is no clear, independent evidence that heated tobacco devices are a better alternative to cigarettes and that they have some harmful effects.

Campaigners wrote to the FDA last year to oppose PMI's IQOS-related applications.

PMI said that in Florida around 3.31 million legal-age consumers regularly use nicotine and that the majority of those smoke.

Adults in Fort Lauderdale will be able to join a wait-list to try IQOS before it becomes commercially available in the city.

(Reporting by Emma Rumney; Editing by Kirsten Donovan)

((Emma.Rumney@thomsonreuters.com; +447391409253;))