Toro Rosso team principal Franz Tost is adamant his Formula One team has nothing to apologise for following its spat with engine supplier Renault at the Brazilian Grand Prix.
Red Bull's sister squad issued a statement on Saturday morning in response to comments from Renault chief Cyril Abiteboul, who suggested the series of recent engine troubles Toro Rosso has suffered may be linked to the way the team is running and installing its power unit.
Tost believes Toro Rosso has every right to be angered, claiming Renault started the spat when Abiteboul spoke to the press on Friday.
"What for should I apologise? For all the damages we have? I am upset as well," Tost told Sky Sports F1. "Both are upset. Who started with all this nonsense? Cyril yesterday with this stupid interview. Should I say 'fine, good interview, we accept it'. No, we don't accept it and that's why we came out with this statement. Nothing to say.
"In the interview yesterday he blamed the team [Toro Rosso], which is absolutely wrong. If we do something that is not OK then we tell it. If the MGU-H or shaft fail it is nothing to do with the installation of the power unit and we have not changed anything regarding the installation of the power unit from the beginning of the season. This is what we wanted to make clear.
Tost also dismissed the notion that Renault could refuse to supply Toro Rosso with engines for the season-ending Abu Dhabi Grand Prix if it felt the Faenza-based squad had broken stipulations within their engine agreement.
"They have a contract. I don't see that we break something [in the contract]. They have a contract, they get a lot of money and they have to supply us with engines. I see it quite easy."
However, the war of words is being fought on both sides, with Renault ambassador Alain Prost taking exception with the wording of the following section of Toro Rosso's statement: "We mustn't forget that they [Renault] are fighting with Toro Rosso for a better position in the constructors' championship, as suggested by Mr Abiteboul the situation may not be a coincidence, but it is certainly not due to STR's car."
Speaking in the paddock ahead of qualifying on Saturday, Prost said: "I just heard what Franz said and obviously there is one thing is for sure, the Renault company has been involved in Formula One for a long time and we've proved we give exactly the same engine to everybody -- which is not the case of the other manufacturers. We would never play any dirty games to gain one position.
"We are struggling at the moment, at the end of the year, I think everyone can see. It's not good for us, not good for Red Bull, not good for Toro Rosso. They will have an engine for Abu Dhabi, there is no question about that, and let's see in the next few hours."
In an attempt to calm the situation, Red Bull advisor Helmut Marko released a statement on Saturday playing down any accusations of unfair treatment.
"Over the last 10 years, many successful, we have been through every emotion with our current engine supplier. As usual at the end of another long season, emotions are running high but it is a valued relationship and will remain so.
"There has never been any question that we have not been treated fairly and equitably by our engine suppliers. And that is still true today."