CHICAGO (Reuters) - A growing number of U.S. states refused on Friday to give voters’ names, addresses and sensitive personal information to a commission created by President Donald Trump to investigate alleged voter fraud, saying the demand was unnecessary and violated privacy.

FILE PHOTO: U.S. President-elect Donald Trump stands with Kansas Secretary of State Kris Kobach before their meeting at Trump National Golf Club in Bedminster, New Jersey, U.S., on November 20, 2016. REUTERS/Mike Segar/File Photo

“This commission was formed to try to find basis for the lie that President Trump put forward that has no foundation,” Kentucky Secretary of State Alison Lundergan Grimes told Reuters in an interview.

Republican Trump has made unsubstantiated claims that millions of people voted illegally for his Democratic rival Hillary Clinton in the 2016 election. He established the panel by executive order in May despite evidence that voter fraud was not widespread.

Trump’s Presidential Advisory Commission on Election Integrity sent a letter to all 50 states on Wednesday asking them to turn over voter information including names, the last four digits of social security numbers, addresses, birth dates, political affiliation, felony convictions and voting histories.

The request from commission Vice Chairman Kris Kobach caused a backlash in states including Virginia, Kentucky, California, New York and Massachusetts, where election officials said they would not provide all the data.

California Secretary of State Alex Padilla said on Thursday that handing over information would only serve to legitimize debunked claims of widespread voter fraud.

More than 20 states said they would not or could not provide some or all of the information requested, according to statements from election officials and media reports.

Some said certain data such as social security numbers were not publicly available and that they would turn over only public information. Others raised privacy concerns or questioned the need to examine voter fraud.

Mississippi Secretary of State Delbert Hosemann said in a statement that he had not seen the letter but would rebuff the commission.

“They can go jump in the Gulf of Mexico and Mississippi is a great state to launch from,” he said.

Kobach, the secretary of state for Kansas, has been a high-profile advocate of tougher laws on immigration and voter identification.

His office did not respond to Reuters requests for comment.

Kobach was quoted in a Kansas City Star article as saying that his own state would not provide social security numbers at this time since they are not publicly available. Kobach did not rule out providing that information in the future.

In his letter, a copy of which was provided to Reuters by the Connecticut Secretary of State’s office, Kobach also asked states for feedback on how to improve election integrity and for evidence of voter fraud and convictions of voter-related crimes since 2000.

Civil rights groups and Democratic lawmakers have called the commission a tactic to suppress votes against Republicans.

“States are right to balk at turning over massive reams of personal information in what clearly is a campaign to suppress the vote,” Dale Ho, director of the American Civil Liberties Union Voting Rights Project, said in a statement on Friday.

While the public availability of voter data varies by state, the request raises privacy concerns, said Richard Hasen, a University of California, Irvine, professor who studies election law.