Michael Schumacher has been given a 10-place penalty on the grid at the next Formula One race for crashing into the back of Jean-Eric Vergne's car in the Singapore Grand Prix on Sunday.

Schumacher made heavy contact with Vergne's Toro Rosso, causing the instant retirement of both cars.

Stewards say Schumacher acknowledged he was to blame, having failed to allow for lower tyre grip that was caused by cooling during a safety-car period.

It was his second similar offence this season, so the penalty was doubled from five to 10 grid spots.

Earlier, the seven-time champion told journalists he suspected a technical failure was to blame.

The German said he was cautious after the end of the safety car period and "braked a little bit earlier than I would normally for that corner" at the fifth turn, leading on to the main straight.

"The car wouldn't decelerate and I need to investigate why that was the case," Schumacher said.

"I just went straight on the brakes very hard, locked up everything and tried to brake as hard as possible but the accident wasn't avoidable anymore."

Vergne, the youngest driver in the field, was forgiving toward the 43-year-old seven-time champion, with both drivers putting an arm around each other as they walked away from their wrecks.

Mercedes team principal Ross Brawn said the crash was "an unusual set of circumstances, so we will have a careful look at the data and work out what could have happened."