The Minneapolis police union put out a call this week for retired officers to help serve as "eyes and ears" at polling sites in "problem" areas across the city on Election Day, at the request of an attorney for President Donald Trump's re-election campaign.

The request was made by William Willingham, whose e-mail signature identifies him as a senior legal adviser and director of Election Day operations for the Trump campaign.

In an e-mail Wednesday morning to Minneapolis Police Federation President Lt. Bob Kroll, Willingham asked the union president about recruiting 20 to 30 former officers to serve as "poll challengers" to work either a four- or eight-hour shift in a "problem area."

"Poll Challengers do not 'stop' people, per se, but act as our eyes and ears in the field and call our hotline to document fraud," the e-mail read. "We don't necessarily want our Poll Challengers to look intimidating, they cannot carry a weapon in the polls due to state law. … We just want people who won't be afraid in rough neighborhoods or intimidating situations."

Kroll then passed on the request to federation members, saying "Please share, and e-mail me if you are willing to assist," according to a copy obtained by the Star Tribune.

Neither Willingham nor Kroll responded to requests for comment Wednesday.

The Trump campaign's call for retired police officers comes amid rising concerns about voter suppression tactics and confrontations.

A Tennessee company recently rescinded a job posting for ex-special forces personnel to show up at polling places in Minnesota after the ad sparked legal challenges and an investigation by Attorney General Keith Ellison. Asked for comment on Wednesday's developments, Ellison's office pointed to a voter guidance statement released this week.

"Minnesotans can also expect that they will be able to vote without intimidation or interference. Minnesota and federal law are clear: it is strictly illegal to intimidate or interfere with voters," the Attorney General's Office statement said. "As Attorney General, I do not expect to have to enforce these laws. But I will not hesitate to enforce them to the fullest extent if necessary to protect Minnesotans' right to vote."

Minnesota Secretary of State Steve Simon said Minnesota law guarantees voters the right to a peaceful polling place free of harassment or intrusion.

"Targeting anyone for a challenge based on being in a so-called 'problem area' is unlawful and will not be permitted in Minnesota's polling places," Simon said.

The e-mail was sent on the same day Gov. Tim Walz and three former Minnesota governors released a public service video warning that the vote counting could take longer than usual and calling for "civility and decency."

Kroll has long aligned himself with Trump, joining the president on stage at a campaign rally last year and more recently echoing Trump's rhetoric while blaming the city's leaders for escalating demonstrations, property damage and violence.

Minneapolis City Council Member Jeremiah Ellison said the "incredibly inappropriate" language in the e-mail seemed to suggest a targeted effort to discourage voters in some neighborhoods.

"To the extent that Bob Kroll wants to participate in a voter intimidation campaign, the city will take that very seriously," said Ellison, whose ward covers parts of the ethnically diverse North Side. "There's the clear dog whistle of 'rough area,' and we need people who aren't 'easily intimidated,' and people who aren't scared."

Under state law, poll challengers are allowed to contest a voter's eligibility "if and only if they have personal knowledge of that voter's ineligibility." They are allowed to be at polling places, but "poll watchers" are not. The only qualifications for challengers are that they live in the state and are registered to vote, but only one challenger is permitted on behalf of each political party per precinct. Law enforcement officers also cannot be stationed near polling places unless called by election workers for help.

Minneapolis and other cities have hired "sergeants at arms," civilian workers who aren't armed, but help election judges ensure that voting goes smoothly.

This week, officials opened two new early voting centers on the city's North and South sides, as they braced for potentially historic turnout. The city said it had received 126,524 absentee ballots as of Monday night.

Police Chief Medaria Arradondo said in a statement that officers will "remain apolitical" in their service.

"We are focused singularly on protecting our residents' most sacred democratic right — the right to safely cast their ballot without intimidation or interference," he said.

Like other departments, MPD has spent weeks preparing for potential unrest or voter intimidation. Days off have been canceled around Election Day, and all officers are expected to be required to be in full uniform and ready to don riot gear in the event of violence.

Department spokesman John Elder said the MPD has made "phenomenal amount of preparations" with other local, state and federal law enforcement agencies "to make sure that we are supportive without being omnipresent."

Civil rights groups have warned about the possibility of voter intimidation, with armed groups threatening to turn up in response to Trump's calls for his supporters to "go into the polls and watch very carefully, because that's what has to happen."

The president's campaign has vowed to raise a 50,000-plus army of volunteer observers to monitor voting across Minnesota and other battleground states, where polls show the president trailing former Vice President Joe Biden.

Minnesota GOP officials say roughly 3,000 people have signed up so far and will get training on state election laws, which forbid campaign workers to interact directly with voters.

On Wednesday, Trump campaign officials announced the president would return to Minnesota for a rally Friday in Rochester, his fourth trip to the state in recent weeks.

Staff writers Stephen Montemayor, Liz Navratil and Kevin Diaz contributed to this report.