There is growing speculation in the US media that White House chief of staff Rahm Emanuel is to leave the White House to run for the mayoralty of Chicago.
The BBC reports that sources close to Mr Emanuel are quoted as saying he will announce a decision as soon as Friday.
Mr Emanuel is a native of Chicago and represented Illinois's 5th district in Congress for six years.
Pundits have tipped Mr Emanuel to replace Richard M Daley, since the latter announced on 7 September that he would step down.
Mr Daley has been mayor of Chicago since 1989. His father Richard J Daley was also mayor.
The BBC reports that if Mr Emanuel does decide to leave, any decision on permanent replacement may not be taken until after the mid-term elections in November.