President Donald Trump slammed the practice of ballot “harvesting,” saying it is “rampant with fraud.”

His comments came in a Tuesday morning tweet. The president wrote: “GET RID OF BALLOT HARVESTING, IT IS RAMPANT WITH FRAUD. THE USA MUST HAVE VOTER I.D., THE ONLY WAY TO GET AN HONEST COUNT!”

Republican officials had told The Washington Post that Trump opposes all-mail elections in which every registered voter is sent a ballot by mail, as well as ballot “harvesting.” The practice allows third parties to collect completed ballots from voters and turn them in.

Last week, Trump tore into the practice of conducting elections by mail, saying it could lead to voter fraud. His comments followed his other claims that holding elections by mail – which is not necessarily the same as voting by absentee ballot – can lead to fraud.