With just two weeks to go before the Iowa caucuses, Republican presidential contender Newt Gingrich tried to launch a counteroffensive Monday against the barrage of negative television ads and mail that his opponents and their supporters are dumping on voters here.

Appearing at a security firm in Davenport, Gingrich gave his most detailed defense to date against accusations that his acceptance of $1.6 million from government-backed mortgage giant Freddie Mac amounted to lobbying and makes Gingrich an ultimate Washington insider.

Gingrich said that over the six-year contract with the Gingrich Group, he personally collected only about $35,000 a year — “less than I was making per speech.” He also stated more forcefully than he’s done to date that he did no lobbying on behalf of Freddie Mac — and that, in fact, he met with House Republicans to urge them to oppose the bailout of Freddie Mac and Fannie Mae.

“It is baloney to suggest that I in any way tried to use any influence with anybody about Freddie Mac,” Gingrich said.

Gingrich’s remarks came at the start of a three-day swing through Iowa at a crucial moment for his campaign: just two weeks before the Iowa caucuses and at a juncture when he is under constant attack from his rivals and has yet to prove that he has the organization and money to fight back.

In his remarks to about 200 Iowans in the vehicle bay of Global Security Services, Gingrich also took a veiled swipe at rival Ron Paul, the Texas congressman, who is among Gingrich’s opponents saturating the Iowa airwaves with negative ads about the former House speaker. Asked about Paul’s foreign policy stances, Gingrich said he didn’t want to speak about his rivals by name. But he went on to criticize those who would advocate for American non-intervention at a time when Iran, led by President Mahmoud Ahmadinejad, is so close to possessing a nuclear weapon.

“The dictator ultimately says in his speeches, ‘I can envision a world in which Israel disappears,’ ” Gingrich said. “Now, I think I know what he means. Some of my colleagues don't seem to understand this."

Additionally, Gingrich’s campaign announced the purchase of about $250,000 in TV time across Iowa, which will be used to air an ad titled “Rebuilding the America We Love.”

And an independent super PAC formed on behalf of Gingrich called “Winning Our Future” has issued a new ad intended to push back against accusations that Gingrich is not conservative enough. However, the video, which has been distributed on the Web, is not yet on TV, a spokesman for Winning our Future said Monday — a fact that reveals the challenges faced by Gingrich and his supporters to build an organization big enough and well-funded enough to reach voters across the early states.

Whether Gingrich can catch up organizationally to his strongest opponents in Iowa — Paul, former Massachusetts governor Mitt Romney and Texas Gov. Rick Perry, all of whom are running ads against him — is the biggest question of the Republican nominating contest. Several recent polls, including one issued Monday by CNN, show that Gingrich’s position as frontrunner has slipped.