Donald Trump alleges error in voting machines in Texas, officials disagree

Trump used the term 'vote-flipping', which describes a correctable technical glitch on older electronic voting machines

In his latest attempt to cast doubt on the election process, Republican US presidential candidate Donald Trump has raised suspicions about the voting machines in reliably Republican Texas despite producing no evidence of an actual problem.

"A lot of call-ins about vote flipping at the voting booths in Texas. People are not happy. BIG lines. What is going on?" Trump on Thursday said in a message to his followers on Twitter.

An email sent to his campaign to determine where the candidate got his information was not immediately returned.

Texas Secretary of State Carlos Cascos, a Republican, said on Facebook that there was no evidence of vote-flipping, a term generally used to describe a correctable technical glitch on older electronic voting machines. Cascos' spokeswoman said he was responding to speculation circulating on social media.

"Our office has received reports concerning rumours that some voting machines may be changing candidate selections when voters cast straight party ballots," Cascos said in his statement, which was posted a day before Trump sent his Twitter message. "We are actively monitoring the situation, and have yet to receive any verified reports of machines changing votes," the statement added.

Cascos' spokeswoman added that the reports the office has received have not come from voters who personally experienced a problem. Local election officials have said the machines are not malfunctioning and some voters may be inadvertently making errors.

"The machines work exactly as intended. There was no vote-flipping," said Shannon Lackey, the elections administrator of Randall County, in the Texas Panhandle.

Vote-flipping generally describes a circumstance in which a voter claims an electronic voting machine -- usually of the touchscreen variety -- changed the selection from one candidate to another. Election officials say those claims usually are traced to user error.

When they do occur, it is typically during a process called straight-ticket voting that is used to select all candidates from one party. Voters might press the button next to a candidate a second time to affirm their choice, but instead wind up de-selecting the candidate.

If voters notice a wrong selection, they can correct it before submitting their ballot.