Civil rights icon and U.S. Rep. John Lewis has been hospitalized for undisclosed reasons.

Citing a statement from Lewis' office, WSB-TV reports that the 78-year-old Georgia congressman was "resting comfortably" in a hospital Saturday night for "routine observation."

The statement says Lewis expects to be released Sunday.

Lewis, a Democrat, played a key role in the civil rights movement and marched with the Rev. Martin Luther King Jr. in 1965 in Selma, Alabama.

Lewis was expected at an Atlanta event Saturday evening but did not attend.