Former US President Jimmy Carter has been hospitalised after developing an upset stomach while flying to Cleveland.
Mr Carter, 85, was travelling there for a book-signing session.
The Carter Centre in Atlanta says he is resting comfortably and is expected to resume his book tour this week.
Mr Carter turns 86 on Friday. He served as president from 1977 to 1981.
Last month, he went to North Korea to secure the release of an American convicted of illegally entering the country in January.
Mr Carter also served as an internal monitor during elections in southern Sudan in April.