U.S. federal prosecutors said Tuesday that one of the biggest online poker sites, Full Tilt Poker, is taking in millions of dollars in bets, but misusing the money instead of keeping it safe to pay out to players.

"Full Tilt was not a legitimate poker company but a global Ponzi scheme," said Preet Bharara, U.S. attorney in New York.

In a lawsuit, government prosecutors contend that Full Tilt Poker's board members and other owners used up the players' money even as players believed they could pull their winnings any time.

Prosecutors said that since April 2007, the company had paid $440 million to board members and other owners. By March 2011, the company reportedly owed $390 million to players around the world, $150 million of which was pulled from Americans. However, the complaint says, it had only $60 million in the bank.

The complaint against Full Tilt and its board both amends and builds upon a criminal indictment against the company and two other Internet poker companies - PokerStars and Absolute Poker - disclosed in April by the prosecutors for the Southern District of New York.

At the time, prosecutors charged that the operators of Full Tilt Poker, PokerStars and Absolute Poker tricked banks into processing billions of dollars in payments from customers in the United States. They said the actions violated a federal law passed in 2006 that prohibits illegal Internet gambling operations from accepting payments.

In the course of that investigation, prosecutors said in the complaint filed on Tuesday that they discovered Full Tilt had "cheated and abused its own players to the tune of hundreds of millions of dollars."