HOUSTON (AP) — Former President George H.W. Bush and his wife, Barbara, remained hospitalized in Houston on Friday, a family spokesman said.

The 92-year-old former president is being treated for breathing difficulties stemming from pneumonia. He was admitted to Houston Methodist Hospital last weekend for shortness of breath but was later moved to intensive care when physicians put in a breathing tube.

He remained in intensive care on Friday, family spokesman Jim McGrath said. No other updates were immediately available, but McGrath said on Thursday that he was hopeful the nation's 41st president could be discharged from the ICU in a few days.

McGrath said former first lady Barbara Bush also remained hospitalized on Friday, after spending her second night at the hospital. The 91-year-old checked into the same hospital on Wednesday for treatment of bronchitis. She reported feeling much better on Thursday after receiving medication and rest.

George H.W. Bush was hospitalized on Saturday and has been in the intensive care unit since Wednesday, relying on a ventilator to breathe. Removing the tube — a procedure known as extubation — would allow Bush to breathe on his own. He was struggling to breathe when he was admitted to the hospital Saturday.

The couple received "an uplifting visit" from longtime friends former Secretary of State James Baker and his wife, Susan, who also live in Houston, McGrath said.

President-elect Donald Trump and President Barack Obama have sent their well wishes, via Twitter and a news conference, respectively. Former President Bill Clinton also tweeted: "41 and Barbara — thinking about you both and sending wishes for a speedy recovery. Love, 42."

The Bushes son, former President George W. Bush, offered thanks on Instagram Thursday for messages "of love and support for Mother and Dad."

"Your prayers are working: 41 and Mom are doing much better today and fighting on," he said in his first public comments about their illnesses. He and his wife, former first lady Laura Bush, were at Trump's inauguration on Friday.

The Bushes were married Jan. 6, 1945, and have had the longest marriage of any presidential couple in American history.