Max Verstappen has said that he suspects Fernando Alonso is looking outside of Formula 1 because the Spaniard's motivation has gone.

Many have hailed Alonso for not only continuing to focus on F1, but also expand his horizons by targeting the 'triple crown' including Le Mans and Indy 500 wins.

However, Red Bull's Verstappen says that he is not interested.

"Doing things outside F1 is something that happens mainly with drivers who are not winning," said the Dutchman.

When asked if he is interested in following Alonso to America and Le Mans, Verstappen answered: "Maybe. If I'm old and slow I will do it.

"When you have the best car on the grid, everyone can win with that car. Any F1 driver could have won in the Mercedes for the last four years. Everyone knows that.

"That's why you don't see Hamilton leaving to do these things because he doesn't need to. It's the same for me. I'm in a position to fight for victories so my motivation is very high and I don't want to do Le Mans or Indycar or whatever."

"My father had the same problem," said Verstappen, referring again to Alonso's change of focus as well as his father Jos.

"[Jos] was in F1 but he didn't win, and there's a moment when the motivation simply disappears and it kills you inside."

The 2018 calendar continues in Germany in two weeks' time.