A dark cloud has moved over the financial health of the United States grand prix in Austin.

The Associated Press reports that race organisers have missed a paperwork deadline and as a result will lose $20 million of government backing.

Economic impact

The missing paperwork is reportedly a mandatory anti human trafficking plan.

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A spokesman for Texas governor Greg Abbott said the state had no option but to not give the Circuit of the Americas (COTA) the funding.

Race promoter Bobby Epstein, and Formula 1 owner Liberty Media, did not comment.

"The State of Texas and COTA have a productive partnership that has had a tremendous economic impact on the city of Austin and the state as a whole, and our office is already working with COTA on this year's race," the governor's spokesman said.