Illinois Governor Rod Blagojevich clung to his office on Thursday despite mounting pressure to quit.
Governor Rod Blagojevich, 52, (Democrat) was charged two days ago with trying to shake down people for political favors.
President-elect Barack Obama has told reporters in Chicago that he has ordered an investigation to find out what if any contacts his staff had with Mr Blagojevich before the governor was arrested on Tuesday.
Mr Blagojevich is accused by federal prosecutors of various bribery and influence peddling schemes, including trying to sell the Senate seat, which Mr Obama resigned after his election.
He has not been indicted and remains governor with full powers.
The selection of someone to fill the vacated Senate seat is in limbo.