Susan Walsh, Associated Press
This March 22, 2013, file photo, shows exterior of the Internal Revenue Service building in Washington.

WASHINGTON — The IRS is signaling further delays in new rules intended to rein in the use of tax-exempt groups for political campaigning.

The agency has announced it won't hold a hearing this summer until it has a revised plan to police loosely regulated big-money political outfits like GOP political guru Karl Rove's Crossroads GPS and the pro-Obama Priorities USA.

The outlines of an IRS plan for new rules on such groups were announced in November and sparked 150,000 comments, many from angry conservatives.

The Internal Revenue Service and the Treasury Department had said they wanted to prohibit such groups from using "candidate-related political activity" like running ads, registering voters or distributing campaign literature as activities that qualify them to be what the IRS calls tax-exempt "social welfare" organizations.