The United Federation of Teachers, one of the city’s most influential labor unions, is expected to make its endorsement in the mayoral race in early June, after further consultation with its members, the union’s president said Monday.

“The next phase of this is really to get more and more input from the membership itself,” Michael Mulgrew, the longtime head of the UFT, said in an interview with NY1. “The number one issue clearly is affordability.”

His comments came days after six Democratic mayoral candidates attended a UFT forum where they outlined their visions for the city’s 900,000 public school students.

At the forum, candidates were questioned on a range of education issues, including mayoral control of schools and how they would navigate potential budget cuts.

Tap the video player above to watch the full interview.