Washington (CNN) -- Rep. Jesse Jackson, Jr., on a leave of absence from Congress since early June, is suffering from a medical condition more serious than initially disclosed, his office revealed Thursday.
Jackson Communications Director Frank Watkins said in a written statement that the nine-term Illinois Democrat "is undergoing further evaluation and treatment at an in-patient medical facility." and "will need to receive extended in-patient treatment as well as continuing medical treatment thereafter."
Watkins declined a CNN request to elaborate on the specific nature of Jackson's ailment.
"Congressman Jackson's medical condition is more serious than we thought and initially believed. Recently, we have been made aware that he has grappled with certain physical and emotional ailments privately for a long period of time," Watkins wrote. "We ask that you keep Congressman Jackson and his family in your thoughts and prayers during this difficult period."
Jackson, 47, has been on leave since June 10. At that time, Watkins said the lawmaker was being treated for exhaustion, and requested that the family's privacy be respected. Jackson's office will remain open for constituent services, the statement noted.
Jackson, the son of famed civil rights leader Rev. Jesse Jackson, represents the Illinois' Second Congressional District. The district includes parts of Chicago's South Side and the Cook County suburbs.
In March, Jackson decisively won a heated primary despite being the subject of an investigation by the House Ethics Committee. The ethics panel has been examining allegations Jackson or one of his associates offered to raise funds for disgraced former Illinois Governor Rod Blagojevich in exchange for the U.S. Senate seat vacated by President Barack Obama.
Blagojevich, convicted on multiple corruption charges, started serving a 14-year prison sentence in March.