A woman seeking to become the first Muslim mayor of a city in the US state of Minnesota has claimed receiving a death threat online.

Regina Mustafa, running for mayor in the city of Rochester, which is about 160km southeast of Minneapolis, said a threat to "execute" was made online by "Militia Movement" earlier this week.

"I have no way of knowing if the person is nearby or across the country," Mustafa told the Post-Bulletin.

On her Twitter page, Mustafa said: "It won't derail me. But any threats must be taken seriously. No one should feel threatened when wanting to serve their community in elected office."

Threat to "Execute" me made online. It won't derail me. But any threats must be taken seriously. No one should feel threatened when wanting to serve their community in elected office. — Regina Mustafa (@cidi_cidimn) February 12, 2018

Mustafa said the threat, made on a post she made on Google Plus last year, has been reported to the police.

Almost 12,000 of Rochester's 114,000 population is Muslim.

In response to the threat, the Council on American-Islamic Relations (CAIR) requested police to investigate the matter.

"We urge state and federal law enforcement authorities to investigate this implicit threat of violence targeting a member of a minority community seeking to take part in our nation’s political process," said Jaylani Hussein, CAIR Minnesota chapter's executive director.

According to a report in the Star Tribune, Mustafa had people shout at her from passing cars.

The report adds that a man walked up to her at a coffee shop last year and told her to "go home".

Rochester Police Department told The Independent that it was investigating the incident but as the threat was directly not aimed at Mustafa, it would be difficult to prosecute the individual.

"I'm concerned they're considering this as harassment," she said.

"I've suffered harassment. I know what harassment is. This is a threat."