Pittsburgh, Pennsylvania - Donald Trump spent the final hours ahead of Election Day stirring up hatred against migrants, including by calling for the death penalty for those who kill US citizens and police officers.

Trump, speaking in Pittsburgh in the battleground state of Pennsylvania, suggested college athletes from Penn State University should be enlisted in his vendetta.

"Oh, those Penn State guys. I wanted them to wrestle the migrants," Trump said.

He also bizarrely said he told UFC boss Dana White to establish a migrant league so they could fight.

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"I think the migrant (league) might actually win. That's how nasty some of these guys are," Trump claimed at his last rally before Election Day.

Later on, he called for the most severe punishment for immigrants who kill US citizens or law enforcement officers.

"I am hereby calling for the death penalty for any migrant that kills an American citizen or a law enforcement officer," he told the crowd, before also promising to do away with sanctuary cities, which generally refuse to cooperate with the criminalization of immigrants.

Trump has taken xenophobic and racist rhetoric to new heights this election cycle, often using fascist notions of the "blood" of the country being "poisoned," while promising mass deportations that he readily admits would be violent.