DENVER (AP) - At least two Colorado tea party groups believe they were caught up in a politically targeted campaign by the Internal Revenue Service to make it hard for them to get tax exemptions after trying unsuccessfully since 2010 to qualify,

The Western Slope Conservative Alliance and the Colorado Tea Party Patriots applied for nonprofit status in 2010. More than two years later, both groups are waiting for official permission to operate under the tax code.

The U.S. Treasury Department's Inspector General has issued a report that found that for more than 18 months, the IRS specifically targeted conservative groups. The IRS has launched a criminal investigation.

Under a special federal tax status sought by the two organizations, participants are prohibited from engaging in political campaigns, but they can promote social welfare issues.

According to the Denver Post, Grand Junction's Western Slope Conservative Alliance said it has been required by the IRS to answer pages of questions about the organization's website and its board makeup. The alliance also was asked to provide detailed agendas for every meeting and all the printed materials it distributed.

The organization's chairman, Kevin McCarney, said federal officials were fishing for answers.

"It was like they were trying to deny us. We still haven't gotten a response," McCarney said.

The Denver-based Colorado Tea Party Patriots applied for tax-exempt status in late 2010.

The group, which is run by Regina Thomson, collects less than $10,000 a year in private contributions to operate, and mostly holds seminars and rallies about voter and constitutional issues, she said.

Thomson said 22 months after the original application, the IRS asked for additional information from the Tea Party Patriots, including all materials being published by the group and a detailed list of past, present and future activities. Because the group missed a deadline, the group has to apply again and pay a $400 fee.

Colorado Republican congressmen quickly weighed in.

"I am appalled by this heavy-handed abuse of power by the IRS attempt to silence the voice of free speech and democracy," said Rep. Scott Tipton, R-Cortez. "It is deplorable whether aimed at conservative groups, liberal groups or any other group that's trying to express their point of view fully within the scope of the law."

Rep. Cory Gardner, R-Yuma, asked Tuesday that the IRS hand over the number of Colorado groups affected by the burdensome questions.

"The revelation that the IRS targeted groups based on their political beliefs is deeply troubling," Gardner said.

Tipton and Rep. Doug Lamborn, R-Colorado Springs, were among a group of more than 60 House Republicans who expressed concern in March 2012 that the IRS was unfairly creating burdensome questionnaires for tea party and liberty groups in Colorado.

Sen. Michael Bennet, a Democrat, encouraged the IRS do due diligence last year.

"We urge you to protect legitimate (tax laws) by preventing non-conforming organizations that are focused on federal election activities from abusing the tax code," Bennet wrote in February 2012.

Bennet spokesman Adam Bozzi said Tuesday the senator believes that targeting any people or organizations based on political ideology is wrong.

"He's glad the chairman has called for an investigation in the Finance Committee and looks forward to getting more information through that process," Bozzi said.