Two men are in hospital and four have been arrested following a fight at Silverstone, police said.
The incident happened between 17:45 and 18:00 BST on Friday near the Ferris wheel at the Northamptonshire venue, which hosts the Formula One British Grand Prix on Sunday.
Four men, aged 40, 35, 35, and 30, were arrested and Northamptonshire Police are appealing for witnesses.
Officers are keen to receive any phone footage of the altercation.
An estimated 106,000 fans were at the circuit on Friday to watch practice for Sunday's race.