Japanese Formula 1 driver Yuki Tsunoda said he was interrogated in his pajamas for several hours by U.S. border control officials before being let into the country for Saturday's Las Vegas Grand Prix.

The racer for Red Bull-owned RB told reporters on Wednesday he had no issues on his two previous visits this year for races in Austin and Miami.

"Luckily, they let me in after a couple of discussions," he said. "Well, a lot of discussions, actually ... I nearly got sent back home."

Tsunoda said he had been travelling with his physio but had to go through immigration on his own and was then taken to a room for questioning despite having the correct paperwork.

The Las Vegas race comes after a three-week break following a round in Brazil and Tsunoda had flown in ahead of the team for a promotional event.

"I was wearing pajamas, so maybe I didn't look like an F1 driver," added the 24-year-old.