FIA president Mohamed Ben Sulayem said it would "not [be] acceptable" for Fernando Alonso to leave Formula 1 while he is in an uncompetitive position.
Alonso, the two-time champion, is out of contract with Aston Martin at the end of this season and earlier this week said that his decision on whether to stay in F1 would be made "not soon".
Aston Martin are 10th in the championship so far this season after producing an uncompetitive car, while engine partner Honda's power-unit is the least powerful on the grid.
What did the FIA boss say about Fernando Alonso's retirement?
Ben Sulayem, the head of motorsport's governing body, said at an event in Madrid on Friday, "There is no way we can allow Fernando to leave - Alonso, a great champion - to leave just because of the circumstances."
"That's not the way to leave the stage. He has to be successful and then he leaves whenever he wants, not because he was forced to leave because of the performance," he added.
Ben Sulayem, whose time as FIA president has been marked by controversy around issues such as removing checks and balances in the organisation's governance, said, "I will be speaking to him. I said to him, I saw him very sad, and I said, 'Fernando, I understand, it's not acceptable that you are coming to your own country and now after two times a world champion…'"
"We did something earlier, in May, legally for the team towards the engine to go and improve, and then I said to him: 'I am not going to tell you what we are going to do. Please tell me what you want because you are the driver and come and tell me what do you want us to do to improve these results.'"
What improvement was Ben Sulayem referring to?
An FIA spokesperson said Ben Sulayem was referring to F1's additional development and upgrade opportunities (Aduo) system.
This gives engine manufacturers whose power-units are assessed to be more than 2% behind the best chances to upgrade its design.
"It is a comment about the Aduo process and that he hopes Fernando Alonso stays in the sport," the spokesperson said. "That is all."