DES MOINES, Iowa (AP) — Republican presidential candidate Newt Gingrich is asking rival Mitt Romney to call off a group airing attack ads that have contributed to the former U.S. House speaker’s slide in the leadoff caucus state.

Iowa and New Hampshire House speakers endorsed Gingrich at the Iowa Capitol Wednesday, a show of force among GOP regulars before the Jan. 3 caucuses.

READ MORE: Coronavirus In Massachusetts: Today's Developments

WBZ NewsRadio 1030’s Bernice Corpuz reports from NH

The pro-Romney group, run by former top Romney political aides, began airing a new ad in Iowa Tuesday. The group will have spent more than $2.8 million on TV attacks this month.

READ MORE: Trail Blazers Rally Past Celtics 109-105

WBZ-TV Political Editor Jon Keller reports from NH

Gingrich, who was interrupted by protesters at the Statehouse in Des Moines, said it would be nice if Romney either disowns the negative ads or admits they are part of his campaign.

MORE NEWS: Mendon Restaurant Staff Stunned By $4,000 Tip Left By Peloton Challenge Team

Copyright 2011 The Associated Press.