Mercedes driver Lewis Hamilton has made a strong start to his campaign at the German Grand Prix by clocking the fastest time in the first practice session of the day.

Hamilton, Fernando Alonso and Sebastian Vettel were the first drivers to head out onto the 5.148km circuit, but it was a poor start for Alonso as he was forced to pull his Ferrari off the track with a mechanical fault.

The Spaniard, who returned to the pits while marshals removed the car, managed to slip back onto the circuit after his garage recovered an electrical problem, only to be sent back to the pits.

The first session ended up being dominated by Mercedes, with Hamilton and Nico Rosberg tussling for the top spot, but it was Hamilton who came out 0.219 seconds faster than his teammate with a time of 1:31.754.

Mark Webber clocked the third quickest time in his Red Bull, while Force India's Adrian Sutil secured fourth ahead of Lotus's Kimi Raikkonen.

Vettel finished eighth with a time of 1:33.213, while Jenson Button placed just above him 1.3 seconds off the pace.

Frist practice full standings:

1. Lewis Hamilton (Mercedes)
2. Nico Rosberg (Mercedes)
3. Mark Webber (Red Bull)
4. Adrian Sutil (Force India)
5. Kimi Raikkonen (Lotus)
6. Felipe Massa (Ferrari)
7. Jenson Button (McLaren)
8. Sebastian Vettel (Red Bull)
9. Romain Grosjean (Lotus)
10. Sergio Perez (McLaren)
11. Paul di Resta (Force India)
12. Nico Hulkenberg (Sauber)
13. Daniel Ricciardo (Toro Rosso)
14. Jean-Eric Vergne (Toro Rosso)
15. Pastor Maldonado (Williams)
16. Valtteri Bottas (Williams)
17. Esteban Gutierrez (Sauber)
18. Charles Pic (Caterham)
19. Max Chilton (Marussia)
20. Giedo van der Garde (Caterham)
21. Rodolfo Gonzalez (Marussia)
22. Fernando Alonso (Ferrari) - No time