Former United States (US) President Bill Clinton’s health is improving but he will remain in a California hospital for at least another night to receive antibiotics intravenously for a urological infection that spread to his bloodstream, his spokesperson said on Friday.

The 75-year-old Clinton, who served as president from 1993 to 2001, entered the University of California Irvine Medical Center on Tuesday evening after suffering from fatigue. He spoke with President Joe Biden on Friday.

The former president’s spokesperson Angel Urena said that Clinton’s white blood count has decreased, indicating his health is improving.

“All health indicators are trending in the right direction, including his white blood count which was decreased significantly,” Urena said on Twitter. “In order to receive further IV antibiotics, he will remain in the hospital overnight.”

Since his admission to the intensive care unit at the hospital, Clinton has received fluids along with antibiotics, his doctors said.

His wife, former Secretary of State and 2016 Democratic presidential nominee Hillary Clinton, was at the hospital on Thursday and Friday, and the two read books and talked about politics, Urena told Reuters.

It remained unclear when Clinton would be released.