FIA president Jean Todt says he will continue doing "as much as we can do" to keep Red Bull in F1 next season.
Red Bull is currently without a power unit deal for 2016 having terminated its partnership with Renault a year early. Mercedes and Ferrari have already both turned down an approach from Red Bull, with Honda saying discussions are ongoing about a potential supply deal despite opposition from McLaren.
Todd says there is only so much influence he can have over power unit supply but insists the FIA will help in any way it can to keep Red Bull and Toro Rosso on the grid.
"As much as we can do, we will do, we have done and will continue doing," Todt said. "It’s very frustrating to see teams like Red Bull and Toro Rosso struggling to get an engine.
"Saying that, I don’t want to judge on that, so probably you have always risen to something that has happened, but we must be as supportive as we can be to allow ourselves to be at the first race next year with both teams with an engine."
Asked if he thinks Red Bull could realistically quit Formula One, Todt replied: "It’s very difficult for me to answer this question because I don’t have the solution in hand.
"I’m sure that Red Bull’s people are working very hard to get a solution and Bernie is supportive as can be to find a solution. As much in my domain as I can do, I will be as supportive as I can and optimistic that Red Bull and Toro Rosso will be in the championship next year. I cannot say more because I don’t have anything for me to be able to say more about that. "
REPORT: Rosberg holds off Hamilton in Mexican GP as Vettel crashes
AS IT HAPPENED: Mexican Grand Prix
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