Lewis Hamilton has questioned the FIA's decision not to investigate teammate Nico Rosberg following the pair's collision at the Belgian Grand Prix.
Mercedes disciplined Rosberg after the German admitted his responsibility at Spa, however FIA race stewards decided it was a "racing incident" that required no further action.
Hamilton said: "Can we race a lot closer and if the other guy is out of the race nothing will happen? Or if it happens again will there be a penalty?
Rosberg's collision with Hamilton ended the latter's race
"We are always asking to be able to race. But there is a fine line."
Hamilton's race at Spa was wrecked in the second lap when he suffered a puncture to his left rear tyre after a collision with teammate Rosberg's right-wing endplate.
The Brit is now 29 points adrift of Rosberg after he was forced to retire late on while his championship rival finished second behind Red Bull's Daniel Ricciardo.