WASHINGTON, Oct 30, 2024 (BSS/AFP) - Donald Trump has seized on isolated irregularities caught by US election officials to claim "cheating" has occurred, amplifying expectations that he will again reject results if he loses next week's vote.

The Republican candidate has consistently declined to commit to accepting the result of the November 5 election, setting the stage for a repeat performance around the unfounded claim that his 2020 loss to Joe Biden was rigged.

On Wednesday, Trump denounced what he said was "cheating" at "large-scale levels never seen before" in the key battleground state of Pennsylvania.

That followed a post from the day prior in which he claimed that "really bad 'stuff'" was occurring in the state, saying "Law Enforcement must do their job, immediately!!!"

Last Friday, officials in one Pennsylvania county announced that they had launched a criminal investigation into a batch of up to 2,500 voter registration applications that had been caught in routine screening.

The county's district attorney, Heather Adams, said the applications had been organized by an outside group as part of a "large-scale canvassing operation."

The revelation has reportedly prompted probes in other counties, and triggered a wave of online misinformation suggesting the registration forms were actual ballots or exaggerating their number.

"Over the past 24 hours, we've seen several videos shared widely online that lacked proper context or were inaccurate, leading to false narratives," said Pennsylvania Secretary of State Al Schmidt.

"Spreading videos and other information that lack context, sharing social posts filled with half-truths, or even outright lies, is harmful to our representative democracy," Schmidt told reporters in a video briefing.

Josh Shapiro, the state's Democratic governor, told CNN Tuesday night that the allegations are "more of the same" from Trump, who repeatedly sought to overturn his 2020 loss.

"We will have a free and fair, safe, and secure election in Pennsylvania," he said.

Pennsylvania, which Trump lost by some 80,000 votes to Biden, is once again among the handful of battlegrounds expected to decide the outcome of the national race.

Polls show Trump in a statistical tie with Democratic nominee Kamala Harris in the state.

When Trump lost in 2020, a mob of his supporters inflamed by his claims of fraud attacked the US Capitol in a violent attempt to keep him in power, and he still baselessly claims to have won that election.