Porsche and Audi are still not ready to confirm their intention to enter Formula 1 for 2026.

During F1's August shutdown, the World Motor Sport Council finally set the new engine rules for 2026 into stone, which the FIA hopes will entice "potential new PU manufacturers" to enter the sport.

Audi, however, is not immediately ready to confirm reports linking it with a Sauber buyout.

"We do not comment on rumours," a spokesman for the Volkwagen-owned German luxury carmaker told DPA.

The other VW brand, Porsche, added via a spokesman: "We welcome the FIA's decisions on the future regulations of Formula 1 from 2026.

"Further details about Porsche's possible entry into Formula 1 will be announced in due course," added the German sports carmaker, which is linked with a 50 percent takeover of Red Bull Racing.

Audi and Porsche now have until August 31 to lodge their official 2026 entries, according to the RTL and ntv broadcasters.

"Nothing has been signed yet," Red Bull's Dr Helmut Marko told f1-insider.com.

"Only when everyone has said yes at the altar is the marriage consummated."

It is clear that Red Bull and Porsche intend to collaborate, however, with the latter even registering the 'F1nally' trademark in the last few days.

SID news agency quotes an Audi spokesman as saying that the FIA's 2026 rules will now be "examined in detail".

"As far as we understand, the process for registering power unit manufacturers for the 2026 season has not yet been initiated by the FIA," the spokesman added.