The mayor of Phoenix has resigned from office to run for U.S. Congress.
Greg Stanton officially stepped down at noon Tuesday, triggering a months' long process for filling his vacated seat.
City officials say Vice Mayor Thelda Williams is serving as interim mayor until the City Council appoints a mayor pro tempore during a special meeting scheduled for June 11. That person will hold the seat until a special election in November.
A Democrat, Stanton entered the office in 2012 after served nine years on the City Council.
Stanton announced his plans in October to run for the House seat held by Democratic Rep. Kyrsten Sinema, who is seeking to fill Sen. Jeff Flake's seat.