Renault Sport F1 boss Cyril Abiteboul says if Red Bull doesn't reach a decision on its 2019 engine plans by the start of next week's French Grand Prix it could withdraw its supply offer.
In Canada, Red Bull closely monitored the performance of Honda's new unit, with junior bull team Toro Rosso collecting extensive data destined to be processed and compared with information associated with Renault's own new latest-spec power unit.
The Milton Keynes outfit intends on doing another comparative analysis in France, after which it will decide the identity of its future engine partner.
Abiteboul has put Red Bull under pressure however, demanding the matter be settled by the end of next week.
"I guess they have all the information that they need now. I don't see why they are going to further delay the decision," Abiteboul told Motorsport.com.
"As per the regulations, [the deadline] was May 15, and then we accepted to extend that a little bit on the back of 12 years of good collaboration.
"But past a certain point, the offer we made, and that they requested, will not stand. It was Montreal that they wanted to wait for: our new spec, Honda's new spec.
"They have all the information, I see no absolutely no reason to delay that any further."
Abiteboul suggests Renault will not accommodate Red Bull in its request to delay its decision until the Austrian Grand Prix, citing logistical constraints.
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"It's simply because we need to source the components," said the Renault manager.
"We're already behind, and it's Renault deciding the timing, not Red Bull.
"Usually we speak after a weekend, we don't do that on Sunday evening, with all the emotions, we let all the testosterone go down a little bit, and we will discuss.
"But we will not be able to wait for the sort of timing that they've mentioned this weekend."
Red Bull motorsport boss Helmut Marko says the team won't succumb to pressure, insisting a decision won't be forthcoming next week.
"He won't get it," said Marko, when asked about Abiteboul's need for a decision.
"I can't tell you anything until Austria. We will have facts which we are waiting for, and we want to be prepared to make the right decision."
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