Verstappen takes to the top with a 1m36.470s, 0.2s ahead of Leclerc.
A 1m36.622s for Leclerc, less than a tenth ahead of Norris.
Piastri completes the top three.
An early fast lap from Bottas, 0.4s clear of Zhou.
Gasly and Ocon complete the top four.
Qualifying for the United States Grand Prix is now underway!
Track limits will no doubt be a major talking point in qualifying based on practice.
Qualifying in Austin kicks off at 10pm UK time.
Verstappen set the pace in FP1, just over a tenth ahead of Leclerc.
Verstappen fastest ahead of Leclerc, Hamilton, Perez, Magnussen, Russell, Albon, Sainz, Hulkenberg and Gasly.
Leclerc has just gone fastest in the first sector.
No one else is out there improving.
Not too many more improvements out there currently.
Zhou improves but stays 16th.
Leclerc and Perez slot into second and third respectively.
Second for Magnussen now, just ahead of Russell.
Hulkenberg slots into fifth.
He sets a 1m35.921s, 0.6s ahead of Albon.
Tsunoda completes the top three.
He goes 0.7s clear of Norris at the top of the timesheets on the softs. Sargeant only fifth, 1.1s off his teammate.
Into the qualifying simulations now with Sargeant and Albon out there on the soft tyre.
Norris, Hamilton, Verstappen, Alonso, Sainz, Tsunoda, Magnussen, Leclerc, Perez and Ricciardo.
Norris takes to the top for McLaren with a 1m37.256s on the mediums - a tenth ahead of Hamilton.
Brake temperature problems down at Aston Martin.
Alonso and Stroll have completed just 12 laps between them.
He manages to keep his McLaren pointing the right way after running off the track. A close one there.
Hamilton, Verstappen, Norris, Tsunoda, Magnussen, Leclerc, Perez, Ricciardo, Zhou and Piastri.
Slow start from Aston Martin: Alonso 17th; Stroll 20th.
Hamilton is cooking out there as he goes a tenth clear of Verstappen.
He slots into P2, just 0.044s behind Verstappen's top time - both drivers on the hards.
Verstappen, Hamilton, Magnussen, Tsunoda, Perez, Zhou, Piastri, Albon, Ricciardo and Norris.