Several Republican presidential candidates have fired back at Democratic presidential frontrunner Hillary Clinton after the latter accused them of trying to make it difficult for Americans to vote.

Republican Ohio Gov. John Kasich, who is considering to run for president, accused Clinton of dividing Americans.

"Don't be running around the country dividing Americans," he said, according to a Fox News report.

He said compared to New York, Ohio has an early-voting period of almost one month.

"Don't come in and say we are trying to keep people from voting when her own state has less opportunity for voting. And she is going to sue my state? That's just silly," he said.

Last Thursday at Texas Southern University, Clinton aimed her criticisms about voting rights against former Texas Gov. Rick Perry, Wisconsin Gov. Scott Walker, New Jersey Gov. Chris Christie and former Florida governor Jeb Bush.

"Here in Texas, former Gov. Rick Perry signed a law that a federal court said was actually written with the purpose of discriminating against minority voters. He applauded when the Voting Rights Act was gutted, and said the lost protections were 'outdated and unnecessary,'" Clinton said.

She said in Wisconsin, Walker "cut back early voting and signed legislation that would make it harder for college students to vote."

Christie, Clinton said, vetoed a bill that would extend early voting.

Clinton also lashed at Bush, saying that when he was still governor of Florida, "state authorities conducted a deeply flawed purge of voters before the presidential election in 2000."

"We have a responsibility to say clearly and directly what's really going on in our country — because what is happening is a sweeping effort to disempower and disenfranchise people of colour, poor people, and young people from one end of our country to the other," Clinton said.

She accused Republicans of "systematically and deliberately trying to stop millions of American citizens from voting."

Walker fired back, saying that "Hillary Clinton's rejection of efforts to make it easier to vote and harder to cheat not only defies logic, but the will of the majority of Americans. Once again, Hillary Clinton's extreme views are far outside the mainstream."

Christie accused Clinton of not knowing "the first thing about voting rights in New Jersey ... or in the other states that she attacked."

Perry spoke to Fox News and defended the voter ID laws.

"When I got on the airline to come up here yesterday I had to show my photo ID. Now, Hillary Clinton may not have had to show a photo ID to get onto an airplane in a long time," he said. "The people of the state of Texas is who she's taking on. Because that was a law that was passed by the people of the state of Texas. She just went into my home state and dissed every person who supports having an identification to either get onto an airplane or to vote."