Villaraigosa also picked up more support Wednesday from his allies in organized labor. United Teachers Los Angeles, which represents teachers in the Los Angeles Unified School District, is spending $13,717 on a mailer to promote Villaraigosa's efforts.
The councilman is a former organizer for the union.
Hahn and former Assembly Speaker Bob Hertzberg also continued their sparring over who would run a more negative campaign in the 13 days before the election.
Hertzberg wrote a letter to Hahn on Wednesday cautioning the mayor for the second time this week against attack ads and renewing his challenge to meet him in a one-on-one radio debate.
"Before you begin an advertising campaign against me, I'm offering you the opportunity to join me in studio to make your case against me to my face," the Sherman Oaks Democrat said.
Hahn campaign spokesman Kam Kuwata said the mayor would not accept the debate offer from Hertzberg because it would "exclude every person of color from the debates." The three other major candidates are black or Latino.
Earlier Wednesday, Hahn and Villaraigosa stood shoulder to shoulder on a street full of red-tagged homes in the Glassell Park neighborhood, consoling shocked residents and expressing sadness about the storm-related disaster.
Times staff writers Jessica Garrison, Patrick McGreevy and Greg Krikorian contributed to this report.