The Circuit of the Americas has hit back at Bernie Ecclestone's claim that Texas might fall off the 2012 calendar.
"Austin? I wouldn't want to put my money down that that will happen," the F1 chief executive said in Abu Dhabi.
Ecclestone referred to apparent differences within the event's organisational bodies, but Circuit of the Americas president Steve Sexton said he was confused by the 81-year-old's comments.
"There is no question that if he wants the USGP race to happen here in 2012, it certainly will," he said in a statement published by the local Austin American Statesman.
"Our funding is secured, and construction is on schedule, so we don't understand Mr Ecclestone's comments. He has expressed great interest in the Austin race and in expanding the F1 brand into the United States."
The Texas project was the brainchild of Tavo Hellmund, but his role as apparently dwindled in recent months as he looks at new possibilities in Mexico, Argentina and Africa.
Our funding is secured, and construction is on schedule
He said on Saturday: "It is now the responsibility of the Circuit of the Americas to make this project happen before Mr Ecclestone's patience runs out."
And Hellmund told The National newspaper last week: "I don't plan to be a track operator. My mission has always been to put the whole deal together and get it going and then continue to broaden my horizons."