By Lara Seligman - 07/30/13 01:19 PM EDT
Weiner has declined to drop out of the race despite admitting that he continued to send sexually explicit online messages to young women, even after he resigned from Congress in 2011 for similar behavior.
Weiner has taken a nosedive in the polls since the latest revelations last week.
De Blasio added that if Weiner drops out, he would not seek his endorsement.
“I think he has invalidated himself as a public figure obviously, so that’s not an endorsement I'd seek,” de Blasio said.