Updated

Republicans controlling the House moved Wednesday to block a new Federal Communications Commission rule requiring TV stations to disclose online information about political ad buys by candidates, political parties and outside groups.

The FCC adopted the rule in April over protests from the nation's broadcasters, who especially objected to having advertising rates disclosed online. The information is already publicly available, but only if one visits a TV station in person to examine it.

The effort to block the FCC rule comes on a bill to fund the agency. It was approved by a House Appropriations panel by voice vote after Democrats lost a party-line vote to strip the FCC provisions from the underlying bill.

The committee vote also came a day after the failed effort in Wisconsin to recall Republican Gov. Scott Walker. More than $60 million was spent on the race, including on TV ads.

House Democrats opposed the move and accused Republicans of seeking to shield large, GOP-leaning political groups from having to reveal information about their ad buys and tactics.

"It looks like you don't want transparency. It looks like you're trying to cover up the fact that all these fat cats are coming in and putting all this money into these elections and they don't want their names to be disclosed," said Rep. Norm Dicks, D-Wash. "All the FCC has required here is for broadcasters to convert documents that have already been assembled to comply with existing law and post it online."

Rep. Jo Ann Emerson, R-Mo., said the new rule is too costly for local television stations and could force them to hire staff to comply.

But Republicans did not try to block a similar new requirement for posting other public information online -- just the rule requiring greater openness about political ads.

The provision faces an uphill slog given opposition in the Democratic-controlled Senate and from the White House. The rule stays in effect in the meantime.

The FCC voted along party lines to require affiliates of the four major networks in the 50 largest TV markets to post the political information online in this election cycle. All stations would have to report such information online in the 2014 election cycle.

The bill to fund the FCC heads to the House floor later this month for a vote.