Red Bull says it will be left with no option but to quit F1 if a deal to race Ferrari engines cannot be reached.
A day after Red Bull-owned publication Speedweek ran an article named "Formula One withdrawal taking shape", the company's F1 advisor Helmut Marko told the official Formula One website that quitting is indeed an option.
"There is an option to stop F1," Marko said. "That is a scenario. If we don't have an engine that allows us to compete at the very front we will prefer to stop."
Red Bull will split with engine manufacturer Renault at the end of the year, meaning it has to look elsewhere for a supply deal. It approached Mercedes first but was knocked back and it is now in negotiations with Ferrari to cut a deal for both Red Bull Racing and junior team Toro Rosso.
Asked what the medium- and long-term future of Red Bull in F1 looks like, Marko added: "I only can look at next year: if we don't have a competitive engine there is no future in F1 for Red Bull Racing. The curtain may go down after Abu Dhabi.
"That is [Red Bull owner] Dietrich Mateschitz's opinion. He knows that it costs the same amount of money to race at the front or, like we are now doing, in the 'premium midfield' - and he is not willing to do that for another season."
Questions remain over whether Ferrari will be willing to supply engines to Red Bull, which has one of the best chassis on the current grid and would be a serious rival for the title. Marko said his team could accept using Ferrari engines that are slightly down on power compared to the works team, but would not accept a big discrepancy.
"If it were a few horsepower less we would not be concerned. But in the end you can check that very easily with the GPS data and other parameters to see what you really get. The truth is that the engine - the hardware - is not the real issue. That is the software and the same fuel."