A UCLA voting rights research center sued the Trump administration Wednesday to block it from using federal databases to allegedly target naturalized citizens who are registered to vote in California.

The UCLA Voting Rights Project filed the lawsuit in the United States District Court for the District of Columbia, alleging that the federal government is interfering with free and fair elections by using unreliable federal records to identify noncitizens who are registered to vote.

The VRP claimed that outdated information and inconsistent records could lead the federal government to misidentify naturalized citizens as noncitizens.

President Donald Trump has urged the federal government to find proof of noncitizens voting in elections ahead of the November midterms and claimed without evidence that tens of thousands of noncitizens are registered to vote, according to the New York Times.

The U.S. Department of Homeland Security requested that California identify noncitizens who are registered to vote in a July 16 letter to Secretary of State Shirley Weber, according to the lawsuit. State officials in New Jersey, Nevada and Pennsylvania also received the letter. The plaintiffs are also asking the court to direct Mullin to rescind his letter demanding the reviews.

Subsequent social media posts from DHS secretary Markwayne Mullin that threatened to arrest and deport noncitizens on voter rolls prompted the VRP to file the lawsuit on behalf of the plaintiffs, said Matt Barreto, the project’s faculty director.

“This created a lot of fear and confusion, and we started hearing from a lot of folks in the community,” said Barreto, a professor in the political science and Chicana/o and Central American studies department.

The VRP’s attorneys, one of whom is California gubernatorial candidate Xavier Becerra, are representing the Coalition for Humane Immigrant Rights – a Los Angeles-based nonprofit that advocates for immigrants’ and refugees’ rights – and Pedro Trujillo, the nonprofit’s director of organizing and a naturalized citizen.

A DHS spokesperson said in an emailed statement that Homeland Security Investigations, a branch of U.S. Immigration and Customs Enforcement, is actively investigating election fraud.

“Under President Trump, HSI is committed to restoring integrity to our election systems and ensuring that American citizens and only American citizens are electing American leaders,” the spokesperson said in the statement.

Mullin claimed in the July 16 letter that the DHS identified 190,832 noncitizens registered to vote in California. Weber, however, questioned the claim’s legitimacy in a July 23 letter to Mullin, arguing that the state had not shared its voter list with the federal government.

Merging records across federal databases and voter rolls – or linking information believed to belong to the same person – can produce incorrect matches because records contain typos, inconsistent names or outdated personal information, Barreto said.

“If you go to any political scientist who works with voter files, they go, ‘Oh yeah, merging is very difficult,’ Barreto said. “You have to take 16 steps to make sure that you have the exact right person, and not just someone that could be that person.”

In other states, the federal government’s estimated number of noncitizens who are eligible to vote has been inaccurate, the VRP alleged. DHS initially claimed nearly 16,000 noncitizens were registered to vote in Nevada but later provided state officials with only 185 identification numbers associated with voters it believed were noncitizens, according to the complaint.

“We’re hoping that the courts will get involved before the midterms and clarify this so that there’s no fear in the immigrant communities,” Barreto said.