New York City Mayor Bill de Blasio, a longtime Clinton ally, won't be attending Hillary Clinton's first major speech as a presidential candidate this Saturday, even though his city will host the event.

Since launching her bid for the Democratic presidential nomination, Clinton has attended relatively small events. This Saturday, she plans out outline her policy vision for the country in a speech and rally on Roosevelt Island in New York.

However, de Blasio told reporters Wednesday that he's skipping the event, the Wall Street Journal reports.

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"I'm waiting to hear, as I've said, her larger vision for addressing income inequality," said the mayor, who has in recent months tried to elevate the national conversation on that issue.

De Blasio managed Clinton's successful 2000 Senate campaign and worked in the U.S. Department of Housing and Urban Development during Bill Clinton's presidency. Mr. Clinton swore in de Blasio last year as mayor.

The mayor also told reporters Wednesday, "I've always liked what I heard from Bernie Sanders," giving a nod to one of Mrs. Clinton's Democratic primary opponents.

While he has yet to endorse a Democratic nominee, de Blasio was also complimentary of Clinton on Wednesday, saying he was "impressed" by her approach to issues like voting rights. Last week, Clinton proposed automatic voter registration while taking Republicans to task for policies that can make voting more difficult for some.

On CBS' Face the Nation on Sunday, de Blasio commended Clinton's proposals. "We have a democracy problem in this country," he said. "We have declining voter turnout. Secretary Clinton put forward a notion we need a national strategy to energize voting again, to get people involved."