Ferrari president Luca di Montezemolo has warned Fernando Alonso about his conduct following comments made by the Spaniard during the Hungarian Grand Prix weekend.
While it is unclear which comments Montezemolo was referring to, the Italian squad suggested Alonso had been critical of the team after a difficult weekend in Hungary.
It also emerged during the weekend that Red Bull was considering Alonso as a contender for a 2014 seat.
In a statement on its website, Ferrari wrote: "There is a need to close ranks, without giving in to rash outbursts that, while understandable in the immediate aftermath of a bad result, are no use to anyone.
"That was a reference to the latest comments from Fernando Alonso, which did not go down well with Montezemolo, nor with anyone in the team."
Ferrari revealed di Montezemolo talked to Alonso today to wish him happy birthday but also warn him about his conduct in public.
"All the great champions who have driven for Ferrari have always been asked to put the interests of the team above their own," Montezemolo said.
"This is the moment to stay calm, avoid polemics and show humility and determination in making one's own contribution, standing alongside the team and its people both at the track and outside it."
Alonso finished a distant fifth in Hungary on a weekend when the team effectively reverted to an old specification package because new parts introduced in recent races had not worked.
The Spaniard said Ferrari was finally getting to the bottom of its problems, but warned that an improvement must come right after the summer break in order to stay in the fight.
"Now we understand the car, we understand the problems," said Alonso.
"We know what parts were not working and in a way it is normal to have this deficit now we are driving with the old parts.
"Over the summer we need to make a step forward that we thought we should make at Silverstone.
"We need these couple of tenths to come immediately for Spa and Monza to have the same performance with the cars we are fighting for the world championships."
The two-time champion has not won a race since the Spanish Grand Prix in May, although he is still in third place in the standings.