A union supporting Hillary Clinton Hillary Diane Rodham ClintonHillicon Valley: FBI chief says Russia is trying to interfere in election to undermine Biden | Treasury Dept. sanctions Iranian government-backed hackers The Hill's Campaign Report: Arizona shifts towards Biden | Biden prepares for drive-in town hall | New Biden ad targets Latino voters FBI chief says Russia is trying to interfere in election to undermine Biden MORE reportedly pressured a labor official to back out of speaking at an event held by Bernie Sanders Bernie SandersMcConnell accuses Democrats of sowing division by 'downplaying progress' on election security The Hill's Campaign Report: Arizona shifts towards Biden | Biden prepares for drive-in town hall | New Biden ad targets Latino voters Why Democrats must confront extreme left wing incitement to violence MORE, the former secretary of State's rival in the Democratic presidential race.

Jeff Johnson, the head of the Washington State Labor Council, was scheduled to speak in Seattle during a "Labor for Bernie" rally, the Huffington Post reported Tuesday. But an international labor union threatened to take away funding from Johnson's group if he spoke at the event, an emcee told the audience at the event.

ADVERTISEMENT

The Washington State Labor Council is affiliated with the AFL-CIO, which has not yet endorsed a candidate for the White House.

Sources told the Huffington Post that the the American Federation of State, County and Municipal Employees (AFSCME) — a member of the AFL-CIO that has endorsed Clinton — pressured Johnson. The AFSCME was not named during the rally.

A senior AFSCME official said in a statement to the Huffington Post that state labor federations are expected to "remain neutral" until a formal endorsement is made.

"As affiliates of the national federation, state labor federations are required to maintain a neutral position in presidential contests until an official endorsement is made by the national AFL-CIO. We expect all state federations to remain in compliance with this policy and where necessary we will exercise the option of withholding funding to ensure compliance with this rule," the official said in the statement.