Red Bull mogul Dietrich Mateschitz has confirmed the threat to pull his energy drink company out of formula one.
His right-hand man and fellow Austrian, Dr Helmut Marko, made the original warning after the Australian grand prix, saying the current rules are preventing the team from ever catching up with its pacesetting rivals.
Red Bull also owns a junior team, Faenza based Toro Rosso.
"Basically what Helmut said was absolutely right," Mateschitz told the Austrian news agency APA.
"We will only stay in F1 if we have a competitive team, and for this you require a competitive power unit.
"If you don't, you can have the best car and the best drivers and still have no chance of competing for the win," he added.
"The problem is that in this area we have no control, as we cannot and will not develop our own engine, simply because we are not a car manufacturer that can justify the investment," said the 70-year-old billionaire.
"A so-called customer engine is also - as everyone knows - not the solution. So we must manage with Renault to get closer to the strength of Ferrari and, in particular, Mercedes," he added.
Also like Marko, Mateschitz is now playing down as "unrealistic" the possibility of selling Toro Rosso to Renault.
"Many topics are always discussed," he admitted, "but as I was not expressly involved, then there cannot have been a lot of talk in this direction."
Renault is also looking into buying other teams, but Mateschitz acknowledged that another option for the French manufacturer is to pull out of F1 altogether.
"Of course it is legitimate for Renault to assess various options, including exiting," he said.
"As an engine supplier, you have the responsibility to supply a competitive power unit, and if you cannot, of course you should leave.
"Equally, the consequences for us would be clear," said Mateschitz.