CHICAGO (CBS) — Local election officials have launched an investigation into suspicious robocalls made to thousands of Chicago election judges over the weekend.

“There is an intent to try to disrupt the orderly administration of the election,” Chicago Board of Election Commissioners Chairman Langdon Neal said.

Approximately 6,000 election judges – mainly on the South and West Sides – received the calls over the weekend, telling them they must report for training, or they would not be able to serve on Election Day.

In other cases, dozens of judges reported receiving calls demanding they vote a certain way in order to serve as election judge.

“If someone’s gonna go to all this trouble for us, what are they gonna do if they just call average voters? They’re not gonna be as inclined, they’re not gonna know who to call if they’re getting misinformation,” said Danny Bravman, an election judge who said he received multiple calls.

Neal said the messages were completely false, and he believes it was a plan to disrupt the election, and perhaps keep down vote totals in Chicago.

“We feel that there was malicious intent, and so we’ve contacted our judges to make sure that that process goes smoothly,” he said.

Election officials said some judges quit after receiving the misinformation. They’re worried other judges might not even show up.

Cook County Clerk David Orr said some suburban election judges also got the robocalls, but the calls specifically mentioned Chicago judges, so suburban election judges ignored the calls.

Orr said extra training is not required, or even offered, beyond what judges received prior to this past weekend.

“We need these judges,” Orr said. “We need them to be where we want them to be. You have to understand, election judges – even if they come from a particular party – on Election Day, they belong to us.”

Bravman said he’s wondering who is responsible for the calls, and the Board of Elections said they’d also like to know. They said Monday night they’re not quite sure who is behind those calls, but they’ll hand over all their information to the state’s attorney’s office.

Neal said federal officials will be called in to help investigate.