TRENTON, N.J. (AP) — New Jersey election officials said Tuesday they have seen no evidence of voter fraud and are not concerned the system is compromised, despite unsubstantiated claims by Republican presidential candidate Donald Trump that balloting in the U.S. is rigged.

"I am a Republican and I have 1,000 percent faith in the New Jersey election system," Hunterdon County Clerk Mary Melfi said.

Phyllis Pearl, the Camden County superintendent of elections for nearly 15 years, said she has "never had problems with voter fraud."

"As an election official, I take it personally. I'm here to maintain integrity of elections for voters and for all candidates regardless of party," said Pearl, who was appointed by former Democratic Gov. Jon Corzine.

The Associated Press reached out to officials in all 21 counties. Eight officials responded and said they had seen no evidence of fraud.

Tuesday's deadline to register to vote on Nov. 8 for races including the presidential battle between the businessman and Democrat Hillary Clinton, comes as Trump increased his claims that the election will be a fraud, tweeting Saturday the race "looks like a rigged election."

While Republican Gov. Chris Christie, a top Trump surrogate who chairs his transition team, has scaled back his public comments on the election, he has said that he doesn't see any evidence of vote rigging.

"I don't think there's danger," Christie said in August of potential vote rigging. "I think the American people ... have faith in the efficacy of our election system."

Lt. Gov. Kim Guadagno, the state's secretary of state who is in charge of elections, told the AP the state Office of Homeland Security is monitoring the situation. She declined to speak further, and an official with Homeland Security did not immediately respond to a call seeking comment.

A study by a Loyola Law School professor found only 31 known cases of impersonation fraud out of 1 billion votes cast in all American elections between 2000 and 2014.

There has been at least one recent conviction on voter fraud charges in New Jersey.

An Essex County employee working for a Democratic state senator in Newark was convicted in 2012 for returning ballots on behalf of the lawmaker from voters who had not cast ballots. Four others pleaded guilty in the scheme, as well.

New Jersey is not considered a battleground state in the presidential contest and reliably votes Democratic in national races.

There are 5.7 million registered voters, according state figures released in October, including 2.4 million unaffiliated voters, 2 million Democrats and 1.2 million Republicans.

New Jersey's election system is run at the county level and overseen by the state.

The state's 21 counties have four-person boards of elections including two people from each party and appointed by the governor. Larger counties also have a superintendent picked by the governor. Counties also elect clerks to five-year terms who certify results and oversee mail-in voting.

The state's Division of Elections maintains a list of registered voters and shares that information so officials in one county can cross-check that a voter hasn't cast a ballot in another part of the state, according to officials. County election officials also have access to motor vehicle records and state and town vital statistics records used to check whether a voter has changed addresses or is deceased.

Officials stressed that it is all but impossible to hack the voting machines because they're not connected to the internet.

Theresa O'Connor, deputy superintendent of elections in Bergen County, said there's no indication of any vote rigging in the state's largest county.

Joanne Nyikita, Burlington County superintendent of elections, said she also has not seen any signs of fraud or rigging.

John Burke, the chairman of the Salem County Board of Elections, who has served on the board since 1996, said he cannot ever remember seeing any evidence of fraud.

He said the biggest problem is voters eager to cast ballots in presidential years, but not being registered to vote.