Jesse Jackson Jr. resigns from Congress

Update below: Jackson Jr. officially resigns

The Chicago Tribune reported Wednesday that, according to his brother, Jesse Jackson Jr. would be resigning "momentarily" from Congress.

Though Jackson Jr. himself did not confirm his departure to the newspaper, he has undergone treatment over the past few months at the Mayo Clinic in Rochester, Minnesota, reportedly for bipolar disorder.

The 47-year-old congressman did not wage a campaign, but easily won re-election this fall for his South Side Chicago district, a seat formerly held by President Barack Obama. Jackson Jr. has been under investigation by the House Ethics Committee for allegedly raising $6 million for then-Gov. Rod Blagojevich (D) in exchange for appointment to the seat.

Gov. Pat Quinn, a fellow Democrat, is required by Illinois law to call a special election to fill the seat should Jackson Jr. resign.

Update (2:36 p.m. Eastern): A spokesperson for House Speaker John Boehner confirmed to the Associated Press that Jackson Jr. turned in his letter of resignation.

Update (3:14 p.m.): Jackson Jr. wrote in his letter, "Over the past several months, as my health has deteriorated, my ability to serve the constituents of my district has continued to diminish. Against the recommendations of my doctors, I had hoped to return to Washington and continue working on the issues that matter most to the people of the Second District. I know now that will not be possible."

He went on to say his constituents deserve a "full-time legislator in Washington," something he cannot be in the "foreseeable future."

"During this journey, I have made my share of mistakes," Jackson Jr. wrote and promised to continue working with federal investigators. Jackson Jr.'s entire resignation letter can be read here, published by NBC Chicago.