Donald Trump appeared to suggest during a rally in Pennsylvania on Friday that the "only way" Hillary Clinton and Democratic congressional candidates can win the Keystone State in November is if they cheat.

"The only way we can lose, in my opinion … is if cheating goes on," Trump told a crowd in Altoona hours after he and Republican National Committee Chairman Reince Priebus made an appearance in Erie.

"I've been all over Pennsylvania and I'm studying and we have some great people here, some great leaders here of the Republican Party and they're very concerned about that," Trump said, referring to those who worry that election fraud could occur when voters cast their ballots Nov. 8.

"And that's the way we can lose the state," he said.

"If we get cheated out of a win in Pennsylvania … especially when I know what's happening here, folks. [Clinton] can't beat what's happening. The only way they can beat it, in my opinion, and I mean this 100 percent, if in certain sections of the state they cheat, OK?"

The comment came shortly after Trump criticized Pennsylvania for failing to reintroduce voter ID restrictions after a state judge struck down an existing law in January 2014.

"I hope you people can sort of not just vote on the 8th [of November], but go around and look and watch other polling places and make sure it's 100 percent fine," he told the crowd. "Go down to certain areas and watch and study and make sure people don't come in and vote five times because if you do that … we're not going to lose."