Washington - President Donald Trump announced Wednesday he would seek a probe into alleged voter fraud after claiming several million people voted illegally in the election that brought him to power."I will be asking for a major investigation into VOTER FRAUD, including those registered to vote in two states, those who are illegal and even those registered to vote who are dead (and many for a long time). Depending on the results we will strengthen up voting procedures!" Trump wrote on Twitter.There is no public evidence of widespread illegal voting in the November election, and Trump and the White House has yet to substantiate the president's claim.Hours after Trump told congressional leaders that as many as five million people could have voted illegally, White House spokesman Sean Spicer said this belief was based "on the studies he's seen"."I think the president has believed that for a while based on studies and information he has," Spicer said.If proven, it would be an enormous political scandal.Spicer said the Republican president nonetheless had confidence in the election outcome.Trump lost the popular vote to Democrat Hillary Clinton by around 2.9 million votes but won the all-important state-weighted electoral college.The president has previously cited a Pew report from 2012 that concluded more than "1.8 million deceased individuals are listed as voters".That report did not provide evidence that dead people voted, or that others voted in their name.Trump has also cited an Old Dominion University study which suggested 14% of non-citizens said they were registered to vote.That study has been dismissed as having flawed methodology, with a sample size of under 1 000 and no link between being registered to vote and actually voting.