Toro Rosso Formula 1 team boss Franz Tost has said he will not apologise for comments made by the team regarding engine supplier Renault amid an ongoing war of words at this weekend's Brazilian Grand Prix.

The situation between engine supplier Renault and Red Bull's junior team has steadily escalated in the last 24 hours, reaching the point of suggestions that Toro Rosso would receive no further engines for Abu Dhabi.

The two parties with the most complex situation in the Red Bull/Renault/McLaren engine negotiations, Toro Rosso agreed to lose Carlos Sainz Jr to the supplier in order to exit their supply contract and move to Honda power.

However, ever since then the team has suffered from appalling reliability, with both Brendon Hartley and Pierre Gasly taking grid penalties for replacement components for the second Grand Prix in a row - and Hartley having never had a penalty-free weekend since he moved to F1.

On Friday, Renault team boss Cyril Abiteboul claimed that Toro Rosso were making internal mistakes, acting as a reason for the failures. Toro Rosso issued a statement to the press and via social media this morning strongly refuting this, hinting that Abiteboul's claims could be linked over their competition for sixth place in the constructors' championship.

Speaking to the media, Franz Tost said that Renault had started "nonsense" and he had nothing to apologise for.

“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," Tost said.

"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.

“What for should I apologise? For all the damages we have? I am as well upset. 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.”
Tost said that where Toro Rosso have suffered repeat reliability issues it is due to having to re-use old elements, even when taking grid penalties for new ones.

“We are also not happy with the situation. The fact is, we don’t get new parts," Tost said.

"We are just changing old parts from one power unit to the next part, and therefore we are suffering. If we change from one old engine to another engine with old parts, then you cannot expect the reliability reaches a high level.”

Asked if it was true that Renault could refuse to supply any further parts for this season, special advisor Alain Prost said there was "no question" they would continue to give Toro Rosso engines.

"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," Prost said.

"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."

Tost meanwhile seemed to suggest the relationship had broken down further than that, saying Renault simply could not refuse, whether they were willing or not.

“They have a contract. I don’t see that we break something [in the contract]," Tost said.

"They have a contract, they get a lot of money and they have to supply us with engines. I see it quite easy.”