Toro Rosso F1 engine situation 'more critical' than Red Bull's

Red Bull and Toro Rosso are without a power supply for 2016 after ending their deals with Renault from the end of this season.

Senior Red Bull figures have made repeated threats to quit F1 if it cannot find competitive engines for its two teams, with Red Bull team principal Horner saying it is up to him to convince Mateschitz to stay.

Ferrari represents Red Bull's best option, after Mercedes made it clear it will not offer a supply, but at present it is understood the Scuderia has only offered an older specification power unit.

"The situation is quite critical because as we sit here we don't have an engine," said Red Bull team principal Horner.

"Toro Rosso are in a similar situation. The timing for them is more critical than Red Bull Racing even.

"It's a slightly different situation for Toro Rosso.

"The important thing for us is to have a first class engine - we'd be in a position where we can't compete [without one].

"Dietrich has made the situation very clear. We'll have to look at another activity.

"Milton Keynes is full of a lot of talent. We would have to look at where we apply that talent.

"First of all we need to conclude our situation with our current supplier."

When asked if there was a deadline to get a deal sorted to ensure the build of 2016's car was not severely affected, Horner said: "It was already difficult two weeks ago. We are late, very late."