Rudy Giuliani was still in the hospital Monday after being diagnosed with pneumonia, as a close associate said the day could be significant for his recovery.

Giuliani, 81, was admitted over the weekend after falling ill with pneumonia, according to his business associate Tom von Essen, who served as New York City’s fire commissioner during the Sept. 11 attacks.

“Rudy had a tough weekend. He had pneumonia,” von Essen said.

“Today is an important day,” he said.

A representative for Giuliani said Sunday that the longtime ally of President Trump was in critical but stable condition due to an unspecified illness, sparking concern and an outpouring of support.

Von Essen said again Monday morning that Giuliani’s condition had not worsened.

“He seems to be doing OK,” added Giuliani spokesman Ted Goodman.