US President Barack Obama has announced the resignation of his chief of staff Rahm Emanuel who is to run for mayor of Chicago.
He praised Mr Emanuel as "extraordinarily well-qualified" for the job.
Mr Emanuel's replacement, at least for the interim, is Obama senior adviser Pete Rouse, who also stood at the President's side for the high-profile send-off at the White House.
The departure of one of Obama's key advisers will be an unquestioned loss for the president.
He relied on Mr Emanuel's intensity, discipline and congressional relationships to keep the White House focused and aggressive.
Mr Obama called it a "bittersweet moment," adding that "we could not have accomplished what we accomplished without Rahm's leadership."