Ferrari's Charles Leclerc secured pole position for his home Monaco Formula One Grand Prix for the second year in a row on Saturday after a crash halted qualifying with 30 seconds remaining.

Leclerc was joined on the front row by Spanish team mate Carlos Sainz, who was unable to complete his final lap after running into Mexican Sergio Perez's crashed Red Bull with the cars blocking the track.

The red flags came out and the session was not resumed.

Perez, who had to go to the medical centre for checks after the session, ended up third with world championship-leading team mate Max Verstappen fourth on a tight street circuit where qualifying is crucial.

Only 10 times since 1950 has the showcase race been won by a driver starting lower than third, but Sunday's weather forecast contains the risk of rain.

"It is very special. I'm so incredibly happy," said Leclerc.

"It's been a very smooth weekend until now. I knew the pace was in the car and I just had to do the job," added the Monegasque, who was fastest in Friday practice and can regain the overall lead on Sunday.

"It went perfectly. That last lap before the red flag was really, really good. Anyway, it didn't change anything for us. The car felt amazing and it's great to have Carlos with me on the front row."

The pole was Leclerc's fifth in seven races so far this season and third in a row. He was also fastest in every phase of qualifying on Saturday.

His time of one minute 11.376 seconds was already comfortably quicker than his rivals, with Sainz 0.225 slower and Perez 0.253 off the pace.

"I don't think that pole was on today, Charles was mighty," said Red Bull boss Christian Horner. "We couldn't have done that time."

Leclerc is six points adrift of Verstappen in the standings after retiring with an engine problem while leading the previous race in Spain eventually won by his Dutch rival.

Leclerc took pole in Monaco last year after he suffered a late crash in qualifying, an accident that also brought out red flags, but he was unable to start the race due to a driveshaft failure.

The Ferrari driver has yet to score a point at home and is seeking to become the first Monegasque to do so since Louis Chiron finished third in 1950.

Perez crashed at Portier, the right-hander before the tunnel, and Sainz was unable to avoid him as he swept around the corner.

"I had to hit the brakes and obviously try to avoid him the best I could," said the Spaniard, who said there were no concerns about his car for the race.

"It's a shame, another a year that a red flag costs us at the end of a session that we cannot go for pole position but this is typical Monaco."

Lando Norris qualified fifth for McLaren, after shaking off the tonsillitis that affected him in Spain, and ahead of the Mercedes of fellow Briton George Russell.

Double world champion Fernando Alonso starts seventh for Renault-owned Alpine, despite also crashing in the final seconds, with seven-times champion Lewis Hamilton lining up eighth for Mercedes but more than a second off the pole time.

Four-times world champion Sebastian Vettel qualified ninth for Aston Martin and Esteban Ocon 10th for Alpine.

Australian Daniel Ricciardo again struggled in his McLaren, qualifying 14th.

"It's frustrating and just confusing to not make these natural steps that one should," he said.

Yuki Tsunoda brought out surprise red flags in the first phase when he hit the barriers, with the AlphaTauri driver continuing back to the pits.

The stoppage wrecked the chances of team mate Pierre Gasly, however, with the Frenchman left with no time to get out of 17th place while Tsunoda returned to qualify 11th. (Reuters)