It follows a tweet from his account on Thursday that said the three-time World Cup winner was "doing fine" in Sao Paulo's Albert Einstein Hospital.
The 74-year-old's personal assistant Jose Fornos also played down the news.
But the hospital said Pele "continues under temporary kidney support, lucid and with no need of breathing support".
The statement added: "[Pele is] improving his clinical condition and remains in the intensive care unit."
Initially on Thursday, the hospital said that Pele had been admitted with "clinical instability".
But later that day, Pele tweeted: "I was simply relocated to a special room within the hospital for privacy purposes only.
"While I appreciate all the visitors that came to see me, I really need to continue my treatment and recovery in peace.
"I am looking forward to spending the upcoming holidays with my family and will start the new year with renewed health, with many international trips already planned! Thank you!"