The Internal Revenue Service said Thursday that it will delay a public hearing that the agency planned to hold this summer until it has revised the controversial regulations it proposed last year for tax-exempt groups.

The agency said it is reworking the guidelines, which are to be the focus on the hearing and have faced vigorous criticism from groups on the right and left. The agency received more than 150,000 comments about the proposed rules during the first public-input phase, which ended in February.

“Given the diversity of views expressed and the volume of substantive input, we have concluded that it would be more efficient and useful to hold a public hearing after we publish the revised proposed regulation,” the IRS said Thursday.

The regulations are meant to govern the political activities of tax-exempt groups, and last year’s revised guidelines called for prohibiting groups from engaging in election-related efforts, including voter-registration and get-out-the-vote drives.

Conservatives have argued that the reform effort is part of an Obama administration attempt to silence critics on the right, while liberals said the first draft of new guidelines simply went too far and required reworking.

The IRS developed the proposals after an inspector general’s report last year revealed that the agency had targeted nonprofit advocacy groups for extra scrutiny based on their names and policy positions.

The agency has said its problematic screening activities started in part because of confusion over how much political activity is allowed for such organizations under current IRS regulations.

IRS Commissioner John Kos­kinen, whom President Obama tapped to lead the agency in the wake of the targeting controversy, said last month that the agency would forge ahead with plans to develop the new guidelines for tax-exempt groups.

“My bottom line is that it’s in everyone’s interest to have clarification,” he said in a Washington Post interview. “My position since I started more than four months ago is that we ought to have clarity, and that any rule that comes out ought to be fair and easy to administer.”