Ferrari has joined Red Bull in questioning the viability of the Formula One teams alliance FOTA.
Amid fears some teams are breaking the gentleman's cost-limiting agreement and faltering talks in Korea, Red Bull chief Christian Horner said the group needs to shape up "or we'll stop".
According to a French language report by the AFP news agency, his Ferrari counterpart Stefano Domenicali also has grave concerns.
"In terms of the cost cutting (disagreement), we can no longer afford to continue like this," said the Italian, referring to the burgeoning debate.
"If there is no trust, there is no need to go forward," added Domenicali.
"We know why FOTA was put together so we need to understand whether we still need it. What are the objectives for the future of FOTA, if it has a future?"
The news of the fracturing alliance will be music to the ears of Bernie Ecclestone, who would prefer to negotiate separately with the teams as F1 looks towards its next Concorde Agreement.