Updated

The Republican National Committee, just in time for Tax Day, is filing a lawsuit against the IRS over what it calls "illegal stonewalling" of its request for documents related to the agency’s targeting of conservative groups.

The RNC said in a statement on Tuesday that the agency, despite several extensions, has failed to produce the documents sought in a Freedom of Information Act request dating back to May 2013. The RNC requested the agency produce correspondence and documents relating to the targeting scandal, in which agents singled out conservative organizations for special scrutiny.

The RNC called the agency’s refusal so far to produce the documents “unacceptable and inexcusable.”

"We're filing this suit because the Obama administration has a responsibility to be transparent and accountable to the American people. The IRS has a legal obligation to answer our inquiry for these records," RNC Chairman Reince Priebus said in a statement. "If the IRS and the Obama administration don't have anything to hide, why not answer the request?"

The RNC-IRS battle is similar to one being fought on Capitol Hill. Congressional Republicans have accused the agency of stonewalling their requests for emails and documents. House Oversight and Government Reform Committee Chairman Darrell Issa, R-Calif., even threatened IRS Commissioner John Koskinen with contempt if his agency does not respond fully to congressional subpoenas.

The IRS claims that it has devoted hundreds of staffers and millions of dollars to complying with records requests pertaining to the targeting scandal, and other aspects of investigations.

At the RNC, the party says the documents it requested are in the public interest because Americans deserve to know how the agency "interprets and enforces the tax laws."

“We’re going to keep fighting to hold the IRS and Obama administration accountable because Americans deserve a government that treats them fairly and not one that harasses them because of their beliefs nor an administration that goes after its perceived political enemies,” Priebus said.