Apr.22 (GMM) Sebastian Vettel has refused to confirm or deny speculation that he is set to graduate to Red Bull's primary team in 2009.

The 20-year-old rookie has impressed from the cockpit of the Toro Rosso outfit so far in 2008; the team that is part-owned, sponsored and supplied with cars by its energy drink parent.

Vettel's contract, meanwhile, is with Red Bull, not Toro Rosso, and Dietrich Mateschitz's racing advisor Helmut Marko admitted recently that the youngster is likely to step up to Red Bull Racing next season.

But on the verge of the DTM race at Oschersleben last Sunday, Vettel insisted: "My focus is on Barcelona and the rest of the season.

"Let's think first about this season," he reportedly smiled to the German magazine Auto Motor und Sport.