'Cheat at your own peril': Donald Trump warns that election laws will be enforced

President Donald Trump, whose 2016 campaign is being investigated by special counsel Robert Mueller, warned voters on Saturday against violating election law during the midterms.

"All levels of government and law enforcement are watching carefully for voter fraud, including during early voting," Trump tweeted.

"Cheat at your own peril," he warned. "Violators will be subject to maximum penalties, both civil and criminal!"