Voting on Election Day? You may have noticed a large number of election monitors posted at polling locations around Fresno County.

The U.S. Department of Justice sent federal monitors to polling sites in five California counties, including Fresno County, on Tuesday, Nov. 4, The Fresno Bee previously reported.

Eligible California residents are voting whether to approve or reject Proposition 50, which seeks to redraw boundaries for many of the states congressional districts.

Who are these monitors, and what are they doing at polling sites? Here’s what to know:

Why are federal monitors at Fresno vote centers?

The U.S. Justice Department is monitoring polling sites at a total of in six counties in the United States “to ensure transparency, ballot security and compliance with federal law” on Election Day, the federal agency said in an Oct. 24 news release.

Federal monitors were dispatched to Passaic County in New Jersey as well as five counties in California.

Those California counties area:

Republican Party representatives previously requested election monitors in certain counties in California and New Jersey, “alleging election irregularities” in “two Democratic states with crucial off-year elections,” CNN reported.

In a statement, California Gov. Gavin Newsom called the Trump administration’s decision to post election monitors at polling sites an “intimidation tactic” meant to suppress support for Prop 50.

“This is not a federal election. The US DOJ has no business or basis to interfere with this election. This is solely about whether California amends our state constitution,” the statement read. “This administration has made no secret of its goal to undermine free and fair elections. Deploying these federal forces appears to be an intimidation tactic meant for one thing: suppress the vote.”

What do election observers do?

The Department of Justice’s Civil Rights Division uses election observers to “help assess compliance with federal voting rights laws,” the federal agency said in a statement published with the release.

Federal election monitors are attorneys who work for the Justice Department, either in the Civil Rights Division or in local U.S. attorneys’ offices. They are not federal agents or law enforcement officers.

These employees are “often highly trained in voting laws” and are dispatched by both Republican and Democratic administrations, “usually in coordination with local officials, to sit at polling locations and watch for instances where federal voting rights laws may have been violated,” CNN reported.

The Civil Rights Division can assign “one or more attorneys and staff members to monitor the election in the field on election day and maintain contact with state and local officials,” the U.S. Justice Department said.

Federal observers would be appointed “by order of a federal court” under the Voting Rights Act to “serve as neutral and impartial observers of election-day procedures,” the agency said in the statement.

Are there other monitors at local polls?

The federal monitors not the only ones watching the local election process.

The city of Fresno has also sent election observers to local vote centers, according to Fresno Councilmember Nelson Esparza.

“Not to say that federal poll watchers are unprecedented, but it’s not a very common occurrence,” Esparza previously told The Bee. “I think in this national environment, that announcement by the federal government has created a confusion and created anxiety. So we, as a city, are saying we will be there, ensuring to our ability that everyone has an easy time voting.”

California Attorney General Rob Bonta previously indicated that he planned to send state election monitors to Fresno County.

When were Fresno County elections last monitored?

It’s been eight years since the U.S. Department of Justice sent election observers to Fresno County, The Bee reported.

Observers from local and state organizations were posted at polling places for early in-person voting in Fresno on Saturday, Nov. 1, and Sunday, Nov. 2, Fresno County/Clark County Clerk/Registrar of Voters James Kus told The Bee.

He didn’t believe monitors from the U.S. Department of Justice were on site during early voting.