But Zeleny appeared unfazed, asking Trump in a tweet to forward examples of fraud.

Trump also attacked CNN directly, tweeting ".@CNN is so embarrassed by their total (100%) support of Hillary Clinton, and yet her loss in a landslide, that they don't know what to do."

Trump responded with a series of retweets of others' comments condemning CNN, including one which was tweeted by a user whose profile indicted he was a 16-year-old boy.

In a televised report, Jeff Zeleny, CNN's chief Washington correspondent, reported that Trump was showing signs of being a "sore winner," adding the president-elect had "zero evidence" to back his claim he won the popular vote or that he was a victim of widespread voter fraud.

Donald Trump fired off another tweet storm on Monday night, attacking a CNN reporter who said the U.S. president-elect "falsely" claimed extensive voter fraud.

There has been no evidence uncovered so far of widespread voter fraud in the U.S. election.

Politico reported that the claim that millions of people voted illegally appeared to have come from an "ultra-right-wing conspiracy website" called Infowars, which Politico said also claimed the Sandy Hook massacre was faked and that Hillary Clinton was a "demon from hell."

In September, voting turnout specialist Michael McDonald, an associate professor of political science at the University of Florida and a nonresident senior fellow at the Brookings Institution, told CNBC that voter fraud was "extremely rare." NBC reported in August that a study of 2,068 alleged election fraud cases in 50 states between 2000 and 2012 found the level of fraud was "infinitesimal" compared with the 146 million voters registered over that period.

While Trump won a relatively narrow Electoral College victory by historical terms in order to win the U.S. election, his Democratic opponent, Hillary Clinton, won the popular vote by more than 2.3 million votes, according to the latest count.

Green Party nominee Jill Stein has crowd-funded around $6.4 million to begin a recount in Wisconsin, where Trump beat Clinton by 27,257 votes, with Stein also likely to initiate recounts in Michigan and Pennsylvania.

The Clinton campaign had not pushed for a recount, but said it would participate to ensure fairness. None of the recount efforts appeared likely to alter the result of the election.

But the president-elect has attacked the recount effort, which he said on Sunday was a "scam," before ramping up his criticism on Monday, when he claimed in a tweet that "I won the popular vote if you deduct the millions of people who voted illegally."

Trump also claimed via Twitter that there was "serious voter fraud" in Virginia, New Hampshire and California, but offered no evidence.

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California's Secretary of State Alex Padilla tweeted at the weekend to say there was no evidence of the fraud claim.

"His unsubstantiated allegations of voter fraud in California and elsewhere are absurd. His reckless tweets are inappropriate and unbecoming of a President-elect," Padilla said of Trump.

David Scanlan, New Hampshire's deputy director of state, told Politico on Monday that the state had "been provided no evidence that suggests that there is voter fraud on a widespread scale."

And in a tweet, Clinton's campaign counsel Mark Elias said, "We are getting attacked for participating in a recount that we didn't ask for by the man who won election but thinks there was massive fraud."

Marc E. Elias: We are getting attacked for participating in a recount that we didn't ask for by the man who won election but thinks there was massive fraud



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