Formula One supremo Bernie Ecclestone has thrown the prospect of next year's proposed Grand Prix of America into serious doubt.
The race, on a street circuit in New Jersey with the Manhattan skyline serving as a backdrop, is scheduled to make its debut next year.
Although the event was announced in October, it is understood to have run into financial, and in turn, contractual difficulties with Ecclestone.
Ecclestone said: "I don't know if it is going to happen.
"I hope everything will be okay. They are sorting things out internally with some of their funds. If they are ready for 2013 we will have them."
Ecclestone's dream has long been to hold a race in New York, but he has confirmed the organisers "are late" with initial payments.
The 81-year-old, speaking to ESPN, added: "We are waiting for different parts of the contract to be agreed."
A race spokesman, however, has refused to confirm Ecclestone's remarks as he said: "We don't comment on our contractual relationship with Formula One or its details.
"We are on track for a June 2013 race, with all course engineering and construction progressing precisely on schedule, a strong management team in place, and strong ongoing support from New Jersey, New York City and the local communities involved.
"We are very confident the 2013 F1 Grand Prix of America will be a great event."
