Formula One supremo Bernie Ecclestone has allayed fears Red Bull may quit the sport - claiming their issues over an engine supplier have been "sorted out".

Much doubt surrounds Red Bull's source of power for 2016 and beyond, with the manufacturer still to officially finalise an apparent split with Renault and yet to announce a new engine provider.

Speculation over the team's continued participation in F1 remains, but Ecclestone provided an optimistic outlook at the Russian Grand Prix on Friday.

He is quoted by the Guardian as saying: "Everything's been sorted out, so I wouldn't worry about it. We don't want them to drop out. I think they have sorted it all out now."

"[Red Bull owner Dietrich Mateschitz] has never fallen out of love with F1. He just wants to be in a position where he can be competitive and that is what will happen, and then he will be OK.

"Wait and see. I wouldn't worry about it."

Earlier in the day, Max Verstappen - who drives for Red Bull's sister team Toro Rosso - insisted he was not worried about losing his drive.

"I am not afraid," the teenager is quoted as saying by motorsport.com. "I am very happy with the contract I have, but if they [Red Bull] don't stay you have to look for other options of course.

"At the moment there is no intention for that. I am not worried about it. I am happy with where I am.

"You cannot change the situation - and I always stay relaxed about it. And if not, I can always go back go-karting!"