Trump tweets about ‘serious voter fraud’ in three states
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President-elect Donald TrumpDonald John TrumpRed states find there’s no free pass on Medicaid changes from Trump Trump meets with Moon in crucial moment for Korea summit The Memo: Trump flirts with constitutional crisis MORE alleged Sunday evening that there were “serious voter fraud” issues in three states during the election, calling out results from Virginia, New Hampshire and California. 

The Twitter accusation capped off an active day on the social media platform for the president-elect. He started the morning saying a Green Party-launched recount in Wisconsin, along with efforts in Michigan and Pennsylvania, will not change the results of the election.

But in the afternoon, he tweeted an unsubstantiated claim that “millions of people” voted illegally and said he would have won the popular vote if those "illegal" votes were discounted.

Trump won 290 Electoral College votes but trails Democratic nominee Hillary ClintonHillary Diane Rodham ClintonDem targeted by party establishment loses Texas primary Penn to Hewitt: Mueller probe born out of ‘hysteria’ Trump claims a 'spy' on his campaign tried to help 'Crooked Hillary' win MORE by more than 2 million in the popular vote tally.

Clinton won all three states Trump singled out on Sunday night. In California, Clinton bested Trump by more than 3 million votes, taking 61.6 percent to his 32.8 percent. In Virginia, she won by 185,689 votes, or 49.9 percent to 45 percent. The margin in New Hampshire was much closer, with some 2,700 votes separating the two.

The claim that people voted illegally has gained traction in conservative circles after being publicized by controversial Infowars radio host Alex Jones, who published an article earlier this month with the headline "Report: 3 million votes in presidential election cast by illegal aliens."

Political fact-checker Politifact has said the accusation is “highly suspect,” and fact-checking website Snopes rates the claim unproven.

Electors will meet on Dec. 19 to certify the results of the Electoral College.