May 26th, 2013 (AFP) - The stewards at the Monaco Grand Prix confirmed on Sunday evening that they had received official protests from the Red Bull and Ferrari teams concerning an alleged illegal Mercedes test session.
In a statement, they said they would hold a hearing with all the concerned parties - Red Bull, Ferrari, Mercedes and tyre suppliers Pirelli - after Sunday's race, won by Mercedes' German driver Nico Rosberg.
The statement explained that the Mercedes team was alleged to have conducted three days of track testing using a 2013 car on May 15, 16 and 17 at Barcelona.
Although Rosberg won in Monte Carlo, Red Bull's Mark Webber said the alleged secret illegal Pirelli tyre test hadn't contributed to their victory.
"I don't think it made any difference here to this race and it just wasn't a major factor," he said.
Pirelli insisted that the test was conducted within the rules.
However, in-season testing is not permitted according to Article 22.4 h) of the Formula One Sporting Regulations of the International Motoring Federation (FIA), the stewards' statement explained.
The statement did not say when the result of the hearing would be known or announced.
Red Bull chief Christian Horner had earlier confirmed his team had taken formal action just hours before the start of the Monaco Grand Prix.
Horner said he had only learnt about the test on Saturday night
"I can understand Pirelli wanting to test the tyres," he said. "They've obviously got issues with the tyres. What's disappointing is it's been done in not a transparent manner. A three-day test has taken place with a current car running on tyres that are going to be used in the next Grand Prix -- and irrelevant of what you call it, that's testing."
He added: "We need to deal with it through the proper channels so that's what we'll look at doing."
It was reported that Mercedes conducted 1000km of running during three days at Pirelli's request.