Updated: 7:45 p.m.

President Jimmy Carter is “resting comfortably” in a Cleveland hospital after having an upset stomach on a plane, The Carter Center said Tuesday in a statement.

“While on a flight to Cleveland, former U.S. President Jimmy Carter developed an upset stomach, and, upon arrival, was taken to Metro Health Hospital for observation. He is resting comfortably and is expected to resume his book tour this week,” the statement reads.

Carter’s grandson, Georgia state Sen. Jason Carter, posted on his Facebook page that his 85-year-old grandfather is “doing fine” and will continue his book tour this week.

The 39th president was originally scheduled to visit a Lyndhurst, Ohio, bookstore Tuesday to sign copies of his book, “White House Diary.”

President Barack Obama called Carter from Air Force One after wrapping up an event about the economy in Albuquerque, N.M., on Tuesday.

“President Obama spoke with President Carter. Sounded like he was doing great, to the point where he’s going to get back on his book tour tomorrow. So we’re all very encouraged by that news,” White House spokesman Bill Burton told pool reporters.