NEW YORK (AP) — Mayors of more than 70 cities are joining forces to support gay marriage.

The mayors of Boston, Houston, Los Angeles, New York and San Diego will co-chair the Mayors for the Freedom to Marry group being formally launched Friday at the U.S. Conference of Mayors in Washington, D.C.

The office of New York City Mayor Michael Bloomberg released details of the announcement on Thursday. The mayors joining the group are pledging to make the case for gay marriage in their individual communities.

The mayors’ group will be linked to the Freedom to Marry advocacy group, which is campaigning to overturn the Defense of Marriage Act.

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