Donald Trump is getting pro-active about concerns the White House race could be “rigged” against him, by recruiting “election observers” to help monitor the vote, though details of the program are unclear -- and are raising concerns about potential Election Day confrontations.

The campaign put out the call for volunteers in a newly added page on its website. The page asks visitors to register to become an election observer and help Trump “stop Crooked Hillary from rigging this election.” 

“I’m afraid the election is going to be rigged,” Trump said Friday at a campaign stop in Pennsylvania, before suggesting he could lose the battleground state if “cheating goes on” in some parts. Noting the state no longer has a voter ID law, he urged voters to “go around and watch other polling areas and make sure it’s fine.”

Trump appears to be tapping into concerns among members of both parties -- Republicans who warn about voter ID fraud and Bernie Sanders supporters who complained about a “rigged” system during the senator’s primary race against Hillary Clinton. Those claims were bolstered by leaked party emails showing Democratic leaders discussing how to undermine him.

But considering the tensions that already have flared outside Trump rallies to date, the possibility of vigilant Trump volunteers looking for voting irregularities has some analysts and officials warning about the implications for Election Day.

“It sounds more like voter intimidation than observation,” Jessica Levinson, a professor at Loyola Law School in Los Angeles who specializes in election law, told FoxNews.com.

Georgia Republican Secretary of State Brian Kemp said he welcomes the monitors but warned, “We don’t want anyone getting unruly,” according to The Washington Post.

A group of GOP lawyers also reportedly is planning an anti-voter fraud effort that includes hundreds of observers on the ground and on call on Election Day.

The Trump campaign did not return a request Tuesday for specifics about its election observer program. But spokesman Jason Miller told The Los Angeles Times the campaign intends to put credentialed observers inside polling places in Pennsylvania and several other states in which they are permitted.

“They will help ensure lawful voters can vote,” he said. “What we’re advocating are open, fair and honest elections.”

As for what Trump’s election observers can or cannot do, election lawyers frequently point to the 1982 case DNC v. RNC.

A federal court essentially said observers can go to polling stations to watch voting and tell state officials about “irregularities unrelated to voter fraud” that could interfere with casting ballots -- including understaffing, long lines and malfunctioning voting machines.

However, they cannot question voters about their credentials, take pictures or videos of them, or hand out fliers about voter fraud and its consequences.

Some Trump critics suggest his comments about the potential for voter fraud in “some parts” of Pennsylvania were really code for saying it will occur in Democratic strongholds like Philadelphia which are heavily populated and where residents could vote multiple times because they don’t need ID.

Thirty-three states have laws requiring voters to show ID at the polls. Supporters of such laws, mostly Republicans, say they prevent election fraud, while Democrats and other opponents argue they were enacted to keep minorities, who mostly vote for Democrats, away from the polls.

On Monday, lawyers for North Carolina GOP Gov. Pat McCrory asked the Supreme Court to re-instate a photo-ID requirement for voters through November, after an appeals court ruled the 2003 law illegally restricts voting by African-Americans.

Critics of such laws argue there’s scant evidence of in-person voter fraud.

“That it could swing an election just isn’t true,” Levinson said. “It’s sad that it has to be conservatives vs. liberal idea. It’s a factual matter.”

Roger Stone, a longtime political consultant formerly on the Trump campaign, agrees with the nominee’s warning about the potential for a rigged election and implied the real problems might come if Clinton wins as a result of voter fraud.  

“I think we have widespread voter fraud,” Stone said in a Breitbart News interview in late July. “I think he has to put [voters] on notice that their inauguration will be a rhetorical. And when I mean civil disobedience, not violence, but it will be a bloodbath. The government will be shut down if they attempt to steal this and swear Hillary in.”