House Democrats overstepped their authority by asking state officials for information as part of an inquiry into allegations of voter suppression, top Republicans on the U.S. House’s investigatory committee said Monday.

The Republicans on the House Oversight and Reform Committee voiced their objections Monday in a letter to Rep. Elijah Cummings (D-Md.), the committee chairman, and Rep. Jamie Raskin (D-Md.), who chairs a subcommittee on civil rights and civil liberties. The two Democrats sent letters to officials in Georgia, Texas and Kansas earlier this year asking for documents related to controversial election decisions in 2018.

“We have serious concerns that your letters appear to be an attempt to insert the Committee into particular state election proceedings, for which we do not see a legitimate legislative purpose,” Rep. Jim Jordan (R-Ohio), the ranking member on the committee, wrote in a letter signed by three other Republicans. “By seeking voluminous records relating to election administration of sovereign states, your investigation offends state-federal comity. In fact, the respective states are already working to resolve any issues with their election administration.”

The U.S. Constitution gives states the authority to determine the “Times, Places and Manner” of elections but also gives Congress the authority to make its own regulations or “alter” state election laws.

The Republicans also wrote directly to the officials in the three states the committee is focused on and suggested the inquiry was not legitimate. One of the state officials, Texas Attorney General Ken Paxton (R), told the committee last week he was rebuffing the request for information. GOP Reps. Chip Roy (Texas), Jody Hice (Ga.) and Michael Cloud (Texas) also signed Jordan’s letter.

Raskin pushed back on the letter in a statement Monday evening, saying the committee had broad investigative power.

“The U.S. Congress has the power and obligation to enforce the voting rights of the people as spelled out in the 14th, 15th, 17th, 19th, and 24th Amendments to the U.S. Constitution, a power we have exercised repeatedly in statutes like the Voting Rights Act of 1965 and the Americans with Disabilities Act to shut down state action hostile to democratic participation,” he said in a statement.

Cummings replied in a statement Monday night, “It’s disappointing that Rep. Jordan is so opposed to oversight at so many levels. With a Democratic President, there was no allegation too small to investigate, but now that Donald Trump is in the White House, there is apparently no scandal too big to ignore. Democrats will do everything in our power to investigate reports of voter suppression, and we expect full compliance with the Committee’s requests.”

In Texas, the committee is interested in the state’s recent careless effort to review noncitizens on its voter rolls. After the state’s top election official and Paxton loudly publicized that nearly 100,000 noncitizens could be on the state’s voter rolls, officials revealed there were significant errors in their data. A federal judge recently instructed the state not to cancel anyone’s voter registration based on the problematic data.

The committee is also seeking documents from Georgia Gov. Brian Kemp and Secretary of State Brad Raffensperger, both Republicans, for documents explaining how the state’s elections were run. Voting rights were a top issue in the gubernatorial race between Kemp and Democrat Stacey Abrams last fall, and some Georgians waited hours in line to vote on Election Day. Kemp also came under scrutiny for serving as the state’s top election official while seeking higher office and for implementing a policy that required someone’s voter registration to exactly match the information on file in a motor vehicle or federal database. Nearly 70% of the people whose voter registration was in jeopardy because of the exact-match policy were black.

Cummings and Raskin also want to know more about why Deborah Cox, the county clerk in Ford County, Kansas, moved the single polling location in Dodge City to a site much more difficult to reach by public transit. The ACLU sued Cox to try to force her to open a second polling location before the election. She has since pledged to open another polling place for future elections.

This article has been updated with statements from Reps. Elijah Cummings and Jamie Raskin.