Mercedes has withdrawn from the group of Formula One teams pursuing greater transparency over the FIA's recent investigation into Ferrari's power unit.
Earlier this month, Mercedes was one of seven teams that wrote to the FIA questioning the settlement between the governing body and Ferrari, and demanding "full and proper disclosure" on the matter.
The letter was in direct response to an FIA statement in late February that confirmed an investigation had taken place over the winter but concluded that details would remain confidential as part of a private settlement with the Italian team.
ESPN understands Mercedes has now pulled its support from the group of non-Ferrari powered teams, leaving just six teams to pursue the issue with the governing body. It is believed the order came from the Mercedes F1 team's parent company, Daimler.
Red Bull has made clear that it intends to continue to push the issue with the FIA, regardless of Mercedes' decision to back down. Team boss Christian Horner recently said the question over whether Ferrari's engine was legal in 2019 also raises questions over the results of last year's championship.
"The whole thing has left a stale aftertaste," Horner told Auto Motor und Sport. "For us, it's about a lot of money. It makes a difference of $20 million whether we finish second or third in the world championship. For each of our employees that is also an additional bonus payment, so we cannot just leave it like that. "
In its original counter statement to the seven teams, the FIA said it had not been "fully satisfied" the Ferrari engine was legal, but opted against pursuing the issue further due to the "material impossibility to provide unequivocal evidence of a breach".
Further questions have been raised by the rival teams in private letters since that statement, but the governing body has only reiterated that it acted appropriately within its judicial and disciplinary rules.
It its public statement, the FIA said: "To avoid the negative consequences that a long litigation would entail especially in light of the uncertainty of the outcome of such litigations and in the best interest of the championship and of its stakeholders, the FIA, in compliance with Article 4 (ii) of its Judicial and Disciplinary Rules (JDR), decided to enter into an effective and dissuasive settlement agreement with Ferrari to terminate the proceedings.
"This type of agreement is a legal tool recognised as an essential component of any disciplinary system and is used by many public authorities and other sport federations in the handling of disputes.
"The confidentiality of the terms of the settlement agreement is provided for by Article 4 (vi) of the JDR."
In their original statement, the seven teams reserved the right to take legal action over the issue but it is not yet clear what the next steps will be.