Red Bull will quit Formula One if engine supplier Renault doesn't manage to build "a competitive" engine, according to company owner Dietrich Mateschitz.
"We'll only stay in Formula One if we have a competitive team, and we need a competitive power unit for that," Mateschitz told the Austria Press Agency on Thursday. "If we don't have one, we can race with the best car and the best drivers and still have no chance of competing for victory."
Mateschitz didn't mention a timeframe for improvement by the French manufacturer, whose contract runs until the end of 2016.
"The problem is, we can't control it," the Austrian billionaire said, ruling out the option of Red Bull starting to build its own engine.
"We are not a car manufacturer who could justify the investment," he said. "So we rely on Renault to close the gap to Ferrari and, above all, Mercedes."
Red Bull swept the F1 driver and constructor titles from 2010-13 with Renault. Despite three wins by Daniel Ricciardo, it lost its dominant position to Mercedes last season following the introduction of turbocharged hybrid engines.
Mateschitz' comments came weeks after the company's motorsport chief, Helmut Marko, sparked a debate about Red Bull's future in the sport following a disappointing showing in the season-opening race in Australia, with Ricciardo finishing seventh and Daniil Kyvat coming in 13th.
"We always look at input and output," Marko said last month. "If the cost-benefit calculation isn't right anymore, it's not to say that we'll continue forever."
Red Bull improved in the next event in Malaysia as Ricciardo and Kyvat came fourth and fifth, respectively. The third race is in Shanghai on Sunday.
For the Milton Keynes-based team, there are hardly any alternatives to Renault.
Being rivals for the championship, Mercedes and Ferrari are excluded as partners, while Honda has an exclusive deal with McLaren.
"Of course Renault can also weigh its options, including a pullout," Mateschitz said. "As a manufacturer, it's your task to deliver a competitive power unit. If you can do that, it's great. If, for whatever reason, you can't do that, you should pull out. Then the consequences for us would be clear, too."