By Jonathan Stempel

NEW YORK (Reuters) - The organizers of the New York City Marathon have been sued by two runners who said the use of a lottery to decide who gets to race in the world's largest marathon is illegal.

In a proposed class-action lawsuit filed on Thursday in the U.S. District Court in Manhattan, Utah residents Charles Konopa and Matthew Clark said the nonprofit New York Road Runners Inc violated New York's constitution by operating a lottery because only the state itself can run chance-based lotteries.

The plaintiffs seek $10.56 million of damages, or twice the estimated amount collected from several hundred thousand runners who from 2010 to 2015 paid $11 nonrefundable fees to try to qualify for the marathon.

They also want an injunction against further lotteries until the Road Runners comply with state gaming laws. Both plaintiffs said they paid to enter the marathon lottery and did not win.

Chris Weiller, a Road Runners spokesman, said the $11 fee is charged to everyone who registers for the marathon, including those who are guaranteed entry to the race. "Our entry process for the marathon is compliant with the law," he said.

Lawyers for the plaintiffs did not respond to requests for comment.

The 26.2-mile (42.2 km) marathon through New York City's five boroughs has been run every year since 1970, except for 2012 in the wake of Hurricane Sandy.

Nearly 99 percent of the 50,235 runners from 125 countries who started the race last Nov. 1 finished, including an 84-year-old woman from the Netherlands.

Thursday's complaint was filed on the same day the Road Runners opened a one-month window for runners to apply for this year's marathon, which is scheduled for Nov. 6.

According to the complaint, fewer than 18 percent of lottery participants win spots in the race each year, and only 14 percent of the more than 80,000 participants did so in 2015.

Runners who actually enter the race must pay fees between $216 and $347. These fees are not the subject of the lawsuit.

The case is Konopa et al v. New York Road Runners Inc, U.S. District Court, District of New York, No. 16-00450.

(Reporting by Jonathan Stempel in New York; Editing by Tom Brown)