Lewis Hamilton says the gap between the top teams and the others in the field is a "serious problem" for Formula 1.

The championship leader said the problem is then compounded by how difficult it is for even much faster cars to overtake their slower rivals.

'It's a difficult situation'

"As you get within five seconds, you immediately feel the effect of the turbulent air," said the Mercedes driver.

READ: We made it hard for ourselves - Hamilton on US Grand Prix

"The other guys are doing their own races so they don't want to slow down much for you. I was stuck behind the Toro Rossos and just couldn't get close to them," Hamilton added.

"It's a difficult situation. The difference in speed between the cars is too much. It's a serious problem for our sport.

"How can Williams and McLaren be three seconds behind?  It's too much. We need to change the rules to reduce these speed differences, and then we'll get great races like we see in MotoGP," said Hamilton.