CHICAGO (Reuters) - Representative Jesse Jackson Jr., who disclosed recently that he has been on medical leave since early June with an unspecified condition, is grappling with "physical and emotional ailments" that require in-patient treatment, his office said on Thursday.

In a statement, Jackson's press secretary Frank Watkins said the 47-year-old congressman's condition was "more serious than we thought and initially believed" and would require "extended in-patient treatment as well as continuing medical treatment thereafter."

The statement did not specify the medical problem.

The Chicago Democrat is the target of a congressional ethics probe for his alleged involvement in the scheme by former Illinois Governor Rod Blagojevich to sell President Barack Obama's former U.S. Senate seat.

Jackson, who has been out on medical leave since June 10, testified at Blagojevich's political corruption trial that he wanted to be named to the Senate seat. But he denied knowing about any offers of money made by his supporters to the then-governor in exchange for an appointment.

Jackson is the son of civil rights leader Reverend Jesse Jackson and was first elected to the House of Representatives in 1995. He has been re-elected by wide margins seven times since.

Earlier this year, he won a competitive Democratic primary against Debbie Halvorson, a former U.S. representative.

(Reporting by James B. Kelleher; Editing by Greg McCune and Vicki Allen)