Washington, Oct 1 (DPA) US President Barack Obama Friday formally announced the long-awaited departure of his chief of staff, Rahm Emanuel, and replaced him with another long-time advisor.

Pete Rouse, Obama’s chief of staff during his time in the Senate from 2005-2008, will serve as an interim replacement. Obama did not say how long Rouse would hold the job, considered by many the second most important position in the White House.

Emanuel was known for an abrasive style that pushed White House advisors to the limit and is credited with helping Obama push through many of his signature domestic accomplishments. Rouse, by contrast, is known for a quieter style that has made him an effective mediator.

‘Obviously these two gentlemen have slightly different styles,’ Obama said, joking that Emanuel was once rendered mute when he broke his middle finger, while Rouse had never seen a television camera he liked.

Emanuel is leaving to prepare a run for mayor of Chicago. While many chiefs of staff serve only two years, the timing of his departure just ahead of November’s mid-term congressional elections is rare. Obama said Emanuel would be sorely missed.

‘This is a bittersweet day here at the White House,’ Obama said, calling Emanuel ‘an incomparable leader of our staff and one who we are going to miss very much.’

A tearful Emanuel responded that it was, ‘needless to say … a bittersweet day for me too.’

The extra time allows Emanuel, a former Illinois congressman, to quickly enter what has become a crowded field of mayoral candidates. Emanuel had long been mulling a run for mayor and must file papers to enter the race by Nov 22.

Yet some pundits have also speculated that the early departure allows Emanuel to be untarnished should Obama’s Democrats suffer heavy losses in November’s election. Voter anger at the White House and sluggish economy has given Republicans hope of major gains.

Rouse will be charged with managing a White House and cabinet in transition. Emanuel is the latest in a string of advisors to announce their departure from the Obama administration, part of a shift that often takes place at the mid-point in US presidential terms.

Others planning to leave include White House economic advisors Larry Summers and Christina Romer, as well as budget director Peter Orszag. US media have speculated that Obama’s national security advisor, James Jones, may also be leaving.

Obama said Rouse, who served for three decades as a staffer in the Senate, was ‘extraordinarily well qualified’ for the task. Rouse had already been serving as senior White House advisor since Obama took office in January 2009.

‘Pete’s known as a skillful problem solver. And the good news for him is that we have plenty of problems to solve,’ Obama said.

Yet Obama has also drawn some early criticism for picking another confidant as chief of staff rather than looking outside the White House.

The president needs more diversity of thought around him,’ Congressman Jim Clyburn, the third-ranking Democrat in the House of Representatives, told US news website Politico. Theory is good. But I would like to see some people who have practical experience, too.’