Red Bull has accused Ferrari of 'playing games' by only offering it 2015 engines, amid the team's growing desperation to find a power unit deal for next year.
The Milton Keynes-based outfit made it clear ahead of the Japanese Grand Prix that it was only interested in securing a deal that would guarantee it performance parity with the works Ferrari team for next year.
However, sources have told Motorsport.com that during discussions over the Suzuka weekend, it was made clear to Red Bull that the only chance it had of a Ferrari deal was for updated 2015 power units.
It is unclear, however, whether this decision is down to the logistical problems of Ferrari preparing an extra two customer supply deals for next year, or because of genuine competitive fears about what Red Bull could achieve with its engine.
In an interview with German publication Auto Motor Und Sport on Monday, Red Bull motorsport adviser Helmut Marko made clear his feelings about the situation.
"They are playing games with us," said Marko. "But we don't want to play along.
"Our consideration to pull out is fuelled more and more.
"It is a cheek to offer us 2015-spec engines when, at the same time, Sauber and Haas F1 are going to get 2016-spec engines."
However, it could yet hold a joker, for a push by Ferrari to allow in-season engine development next year requires unanimous support to happen.
Without it, Ferrari would have to join other manufacturers in ensuring that their engines are fully homologated by February 28.
However, such a stance would not go down well in terms of getting the relationship with Ferrari off to a good start.