Real Madrid do not want Ronaldo to leave the club but are prepared to continue negotiations with AC Milan over the future of the Brazilian player, according to the club's sporting director Predrag Mijatovic.
"We don't want to sell Ronaldo but it doesn't depend on us," Mijatovic said at the Champions League draw in Monaco on Thursday.
"We are talking with Milan out of respect because they are a great club and there are still three or four days in which we can continue talking."
Milan vice-president Adriano Galliani and sporting director Ariedo Braida were in Madrid for talks with Mijatovic on Wednesday but returned to Italy after failing to reach an agreement.
Spanish media reported that Milan had offered 22 million euros ($28.22 million) for the three-times World Player of the Year who played for their city rivals Inter for five years before moving to Real for 45 million euros in 2002.
The nine-times European champions are reported to want close to 30 million euros for the striker and are hoping to get a preferential option to buy Milan's Brazilian midfielder Kaka included in the deal.
"The player is very happy at Real Madrid, but I understand that he has to evaluate the offer because he is a professional," said Mijatovic. "I would like him to stay. He is happy and for us to let him leave it would have to be a very important offer."
Real have said that Inter are also interested.
Ronaldo, who will turn 30 next month, has notched up 100 goals since joining Real and has been top scorer in each of his four seasons at the club.