Aug.1 (GMM) A hydraulic problem sidelined Sebastian Vettel's Toro Rosso during the morning practice session in Hungary on Friday.

After just four laps of the twisty 4.4km Hungaroring circuit near Budapest, the German driver ground to a halt and finished the 90 minute session slowest of the twenty cars in action.

"It was a problem with the hydraulics. It's not the end of the world," Vettel, 21, confirmed to reporters at the track.

Vettel said he will be back in action in the afternoon.