Mayor Bill de Blasio issued a stern warning to anybody thinking of answering Donald Trump’s calls for supporters to watch polling sites on Election Day: the city “won’t tolerate” it.

Trump has repeatedly claimed that the presidential election will be “rigged,” going so far as to say during the final presidential debate that he’ll keep the nation “in suspense” about whether he would accept the outcome. New York City from another local figure has also seen similar allegations: from Manhattan Board of Elections Commissioner Alan Schulkin, a Democrat caught on a conservative reporter’s hidden camera describing voter fraud in minority neighborhoods (The mayor has called for Schulkin’s resignation.)

“We won’t tolerate any voter intimidation so if we obviously our officers are prepared if there is any systematic effort to disrupt it,” de Blasio said at an unrelated press conference at One Police Plaza.

When a reporter asked whether voter intimidation was in issue during the 2012 presidential election, both Police Commissioner James O’Neill and Chief of Patrol Terence Monahan said it was not a problem at that time.

In the wake of Federal Bureau of Investigation Director James Comey’s announcement that he found previously unknown emails related to the FBI’s investigation of Clinton’s private server found in the inbox of disgraced former Congressman Anthony Weiner, a few polls suggest Trump has recovered some lost ground in his battle with Hillary Clinton.

The mayor noted that voters are not allowed to enter polling sites with partisan materials. Chief of Department Carlos Gomez said officers at polling sites, election inspectors from the New York City Board of Elections and the NYPD Legal Bureau will be on hand.

“They’re just a phone call away,” Gomez said. “Any issues that arrive, we expect the officer to call the supervisor and if they’re not sure of what course of action to take, we’ll check with our Legal Bureau and we’ll be advised by them as to what to do.”

A Trump supporter was recently arrested and charged with electioneering when he wore a hat in support of the Republican nominee and a T-shirt with the phrase, “Basket of deplorables” as he was going to vote early in Texas. In Iowa, another Trump supporter faces allegations of voting twice.

On Election Night, Clinton will deliver remarks to supporters and reporter at the Jacob Javits Convention Center in Manhattan. The Trump campaign has not yet provided details about his plans next Tuesday.

Disclosure: Donald Trump is the father-in-law of Jared Kushner, the publisher of Observer Media.