American-owned F1 team Haas carried on racing without the sponsorship of Russian company Uralkali on its car Friday amid increasing disquiet on the final day of preseason testing in Barcelona where Mercedes and Red Bull were the fastest in early action.

Haas F1 has removed the Uralkali sponsorship from its Formula One cars.

Haas F1 has removed the Uralkali sponsorship from its Formula One cars. (AP/Getty Images)

Haas' driving lineup includes Nikita Mazepin, the only Russian driver on the Formula One grid this season. Its decision on its plain livery came after four-time champion Sebastian Vettel said he would not race at the Russian Grand Prix in September because of Russia's invasion of Ukraine.

"Haas F1 Team will present its VF-22 in a plain white livery, minus Uralkali branding, for the third and final day of track running at the Circuit de Barcelona-Catalunya," the team said in a statement Friday. "Nikita Mazepin will drive as planned in the morning session with Mick Schumacher taking over in the afternoon."

Haas F1 fields cars driven by Mick Schumacher of Germany and Nikita Mazepin of Russia.

Haas F1 fields cars driven by Mick Schumacher of Germany and Nikita Mazepin of Russia. (Hasan Bratic/DeFodi Images via Getty Images)

Formula One later pulled its race from Russia, saying it would be "impossible" to hold the race in Sochi under the current circumstances.

Mazepin has not yet spoken publicly after Russia's attack on Ukraine. He and team principal Gunther Steiner canceled media appearances Thursday.

Mazepin's test run was cut short because of a suspected leak. A coolant leak had reduced the team's time on track on Wednesday.

Haas receives significant funding from Uralkali and had unveiled a white, blue and red livery that resembled the Russian flag. The car Friday had the word "Haas" in big red letters on its side.

"No further comment will be made at this time regarding team partner agreements," the team owned by Gene Haas said.

The Uralkali livery featured the colors of the Russian flag.

The Uralkali livery featured the colors of the Russian flag. (Dan Istitene - Formula 1/Formula 1 via Getty Images)

George Russell was fastest in the morning session with Mercedes, ahead of the Red Bull of defending world champion Max Verstappen, Vettel for Aston Martin and Ferrari's Charles Leclerc.

After no major incident during the first two days, the final session was red-flagged five times in the morning — first because of an issue with the Alpine of Fernando Alonso and then because of a crash by Pierre Gasly into the tire barriers with AlphaTauri.

Pirelli will artificially soak the track in the afternoon session to test wet tires. Among the sweeping regulation changes to try to improve racing in 2022 was the addition of bigger tires. All 20 drivers were expected to hit the track.

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Another three-day test period is scheduled for March 10-12 in Bahrain ahead of the season-opener there on March 20.