"Millions of illegal immigrants want to invade our country and violate our laws," Trump said during a campaign rally in neighboring Ohio on Monday. "If you want open borders, vote Democrat."
But as the clock ticks down to the opening of polls on Election Day, it remains unclear whether Trump's message will resonate with voters or backfire.
Many observers see Trump's rhetoric on immigration as an attempt to stoke fear in order to increase voter turnout among his mostly white base especially in states like Pennsylvania.
"I think he [Trump] recognizes that a lot of the folks that will come out and vote for him, they respond to those dog whistles, so if the dog whistle works, then that’s what they employ," Brandon Flood, Political Action Chair for the Pennsylvania NAACP told Sputnik.
But while Trump's immigration message could prove popular among his supporters, his rhetoric is drawing criticism for what some see as a blatant attempt at fear-mongering that runs counter to American values.
In fact, some of Trump's stances have proven so controversial that they have raised eyebrows even among his most ardent supporters.
On Monday, Fox News, a TV station that is generally supportive of Trump, joined other major news outlets in announcing that it would stop running a controversial immigration ad paid for by the Trump campaign.
The ad centers on the story of Luis Bracamontes, an undocumented immigrant who killed two police officers in the state of California. The message has drawn criticism not only for being divisive, but also because it is inaccurate: It wrongly asserts that Democrats allowed Bracamontes to reenter the country after he was deported, when in fact he returned to the United States during Republican George W. Bush's presidency.
The controversy over the ad has raised concerns among Republicans, many of whom fear that Trump's message on immigration could inadvertently draw a backlash from US voters.
Senior Republican leaders reportedly fear that by harping on the immigration message, Trump has adopted a dangerous election strategy and forfeited the opportunity to highlight his own successes, such as the economy.
House Speaker Paul Ryan is so concerned about the current state of competitive House races that he called Trump on Sunday to implore him to spend more time focusing on the economy, rather than immigration, Politico reported, citing a source familiar with the call.
Democrats, meanwhile, are seizing on Trump's fear-mongering to garner support of their own, taking aim at his immigration policies in the campaign.
"The only caravan you should be careful of are the thousands of Democrats and the thousands of Independents migrating from the sidelines and making sure you never come back to Washington DC," Pennsylvania State Rep. Patty Kim told supporters at a campaign rally on Sunday, drawing enthusiastic cheers.
"We have to reset the moral compass of this nation," Biden said. "We have to choose hope over fear, choose unity over division, choose our allies over enemies, and most of all, we choose truth over lies."