Christian Horner says Red Bull are waiting for Renault to confirm their commitment before making any plans for the future.
Speculation has swirled this weekend at Spa that the former world champions are angling for an engine deal with Mercedes. Horner described reports that Red Bull have served a quit notice on Renault as "complete speculation" but stopped short of denying the claims.
"The bigger question is what are Renault's plans for the future – and hopefully that will be forthcoming in the next few weeks," Horner said,
"That [Red Bull's plans] depends on Renault. We have an agreement with Renault until the end of 2016 and anything more than that is speculative."
Renault are understood to regard their 2016 deal as binding, but Horner added: "Our aim is to be as competitive as we can as quickly as we can and first of all we want to understand what the situation is with Renault and what commitment they have to reducing the deficit."
Red Bull owner Dietrich Mateschitz warned earlier this year that the team would be prepared to leave F1 unless they secured a supply of competitive engines while a divorce from Renault, one of only four power providers in the sport, would also leave the team at risk of being unable to continue.
"The bigger danger is if we don't manage to address our current situation then the damage would be significant," said Horner. "You heard Dietrich's comments and it is important not to take them too lightly. We have to address the competitiveness of the team moving forward. We want to hear what Renault's plans and commitments are and what that entails. Once we understand that, we can make a plan."
It has been widely reported that Red Bull's reputed quit notice cited performance-related clauses which the former world champions don't believe their partners have met.
"We have a contract with Renault and there are obligations on both parties," Horner added. "The key thing within the current F1, that you could see at this circuit, is that the key performance differential is the power unit and you struggle to compensate too much with the chassis and there are some significant gaps."
Asked to elaborate on Red Bull's concerns about Renault's current level of commitment, Horner replied: "It needs a root-and-branch review. There are some very capable people at Renault but it feels under-resourced. There is no silver bullet – it is probably an element of everything: equipment, personnel, and obviously finance is required for that."