Lewis Hamilton is perplexed as to why Red Bull might "give up" on Formula One as a result of their failure to remain the dominant force in the sport.

Red Bull team principal Christian Horner recently admitted he has a tough task to convince co-founder Dietrich Mateschitz to continue in F1.

Sebastian Vettel was crowned champion four years in a row with Red Bull also winning the constructors' title in each of those seasons, until Mercedes ended their dominance in 2014.

Red Bull say their F1 future, along with that of junior team Toro Rosso, depends on being able to agree a deal for a competitive engine as their contract with Renault comes to an end this year.

But world champion Hamilton, who is on course to retain his title, has spoken of his disappointment that Red Bull should even consider turning their back on F1.

The Mercedes driver said: "It seems really odd for me, having witnessed Red Bull's success and then the moment they don't have success, it's like they have been upset about it, I have not seen that with any other team.

"Growing up, watching Formula 1, when Ferrari lost the championship after having success, I don't remember - but maybe they did - hearing them complaining the next year.

"You have to keep pushing forward and there is no reason for them to give up."

Hamilton added ahead of the Russian Grand Prix this weekend: "It would be a shame for the fans (if Red Bull pull out).

"They have a great team, great drivers, great pedigree, they have had incredible success, and they still have a pretty awesome car.

"They can still have success - they just have to work hard at it."