Washington's secretary of state blasted the Justice Department Wednesday after federal officials said investigators had identified more than 400 noncitizens illegally registered to vote in the state, some of whom they said had cast ballots in multiple elections dating back decades.

Washington Secretary of State Steve Hobbs pushed back against the findings, saying the state’s review of the list uncovered "several glaring deficiencies." "This list includes United States citizens and is not reliable. Without individualized proof of ineligibility, it would be both irresponsible and illegal for election officials to decline to process a registered voter’s ballot," he said. "That analysis reflects a significant number of people on your list who are not currently registered to vote or are on inactive status, contradicting your representations that all the individuals included in the list will receive a ballot in this year’s election," he added.

On Monday, the U.S. attorneys’ offices for the Eastern and Western districts of Washington said investigators had identified lawful permanent residents, or green card holders, who were registered to vote or had cast ballots. "We have identified over 400 noncitizens who are registered to vote and have voted in multiple elections. This is only the tip of the iceberg," Neil Floyd, acting U.S. attorney for the Western District of Washington, said in a statement. "We will continue to investigate and identify those who are committing crimes by voting illegally."

Immigration officials told Fox News Digital Tuesday that dozens of noncitizens have also been arrested nationwide in a major voter fraud crackdown.

In an interview with Fox News Digital, Floyd said investigators identified hundreds of noncitizen voters by reviewing U.S. Citizenship and Immigration Services (USCIS) records, which showed that some people who applied for certain benefits had also voted.

While some individuals voted only once or three times in past elections, Floyd said others voted as many as 27 times. In total, his office counted approximately 1,500 instances of noncitizens casting ballots. He emphasized that some noncitizens had been voting for decades, predating Washington’s transition to a vote-by-mail system. "I think the earliest moment we have is 1984," Floyd said. "It's early ‘90s, late ’80s, I believe." However, Floyd said he had not checked whether any of the individuals voted in the upcoming midterms, explaining that he did not want to "interfere with the current election."

The number of potential noncitizen voters could represent only a fraction of the broader population, Floyd said, because the list includes only individuals who sought certain benefits in Washington state. "If you take that population, and you expand it out to include all the people that are here illegally that we haven't had contact with, just my estimation is that it's going to be in the thousands," Floyd said.

Federal officials said many green card holders were registered to vote without their knowledge through Washington’s Motor Voter program, which integrates voter registration into the state’s Department of Licensing. "We have heard from green card holders who were registered against their knowledge via the Washington Motor Voter program. Then they receive a ballot in the mail and assume they are legally registered — that simply is not the case," the notice said.

According to the Washington secretary of state’s website, eligible residents are automatically registered to vote only if they provide proof of U.S. citizenship during a driver’s license or ID card registration process. Floyd said investigators identified patterns they believe contributed to noncitizens being registered to vote.

According to the DOJ notice, federal officials are asking Washington state to set aside ballots cast by the identified individuals until their citizenship status can otherwise be confirmed. "Washington is now on notice that noncitizens are voting. It is up to the state to take action to make sure that they are not allowing these noncitizens to vote illegally," the notice said.

The move builds on DOJ's legal action against California, where federal officials are seeking to set aside mail-in ballots from roughly 20,000 voters they allege are likely noncitizens while their citizenship status is verified. In response, the California secretary of state’s office said last week that its review "found significant accuracy problems with their sweeping claims."" At best, this litigation is a reckless political stunt.

At worst, it threatens to disenfranchise thousands of Californians this election. Plaintiff’s sole claim—that a federal criminal prohibition on individual noncitizen voting preempts large swaths of California’s election administration—borders on the absurd. The relief Plaintiff seeks is as unlawful as it is untenable," the statement said.

Officials warned that voting as a noncitizen can have serious consequences for those seeking to become U.S. citizens. Potential criminal charges include making false statements in a naturalization application, and some individuals could also face charges for fraudulent voter registration.

On Tuesday, the Department of Homeland Security told Fox News Digital numerous illegal aliens had also admitted to unlawfully registering to vote or casting ballots in U.S. elections. least 18 had voted in a federal election. The individuals were from a range of countries, including Mexico, Somalia, Honduras, Guyana, Cuba, Germany, Nicaragua, Venezuela, Vietnam, El Salvador, Cambodia, Guatemala, Portugal and Italy.

Many also faced charges for numerous alleged crimes, including counterfeiting, fraud, kidnapping, DUI, sexual offenses, assault with a dangerous weapon, drug possession and burglary.