Dani Pedrosa claimed his third MotoGP pole of the season in a dramatic qualifying session at Indianapolis on Saturday, which saw team-mate Casey Stoner suffer a nasty accident on his fourth lap.

Stoner's fall was the first of two red flag periods. Ben Spies and Nicky Hayden also fell through the same Turn 13-14 left handers, Hayden halting the session with eight minutes remaining.

Pedrosa had taken over at the top from Spies after 22 minutes and kept out of trouble as he remained at the head of the standings to the end of the 60 minutes of track time. The Spaniard's best lap was his 25th of 27, which put him 0.1s clear of title leader Jorge Lorenzo (Yamaha).

Lorenzo will start Sunday's race with a 23-point advantage over Pedrosa.

"It was a tricky session because the asphalt was very slippery and we saw many nasty crashes already in Moto3 and then in MotoGP," said Pedrosa, winner at Sachsenring earlier this season.

"It felt like you could control the slide, but suddenly it goes quick. So it wasn't easy to find the edge. Maybe that's why many riders crashed.

"But fortunately we did not see anybody run into a wall or against other riders. So there is not a safety issue with the track layout."

Looking ahead to Sunday's race, Pedrosa added: "To be in pole position is great at a track where the first sector is very tight and it's always good to have a clean start. We did a very good job today, testing the tyres, working on the bike and being ready for the hot laps. I feel we have a good setting for tomorrow.

"We are confident for the race, but other riders look strong as well. Lorenzo picked up his pace, Spies is strong here and I hope Casey has nothing serious and can be on the grid. We will need to fight at the maximum tomorrow".

Reigning world champion Stoner was immediately taken to the circuit medical center after his accident.

The first X-Rays ruled out any serious injury, suggesting torn ligaments in the right ankle. Stoner was then taken to the local Methodist Hospital for further checks and scans.

Repsol Honda will release a statement later today, as soon as more information is known.

Stoner, who was fastest in final free practice, qualified in sixth position despite completing just three flying laps.

Hayden has already been ruled unfit to race after being briefly knocked unconscious, while Spies hopes to ride despite a painful shoulder.