(CNN) The head of House Republicans' campaign arm defended abruptly pulling out of late-stage negotiations with Democrats on a pledge to reject using hacked materials in election ads, citing an erosion of trust between the parties.

But National Republican Congressional Committee chairman Steve Stivers, an Ohio congressman, on Friday also took his strongest public stance to date against using such illicit materials, telling reporters, "We are not seeking stolen or hacked material, we do not want stolen or hacked material, we have no intention of using stolen or hacked material."

Stivers and his Democratic counterpart, New Mexico Rep. Ben Ray Lujan, have been in talks since May to try to reach an agreement on a pact, which they hoped would send a strong message against election interference in the lead-up to the midterms.

The exercise was not purely symbolic, however. After Russian hackers penetrated the Democratic Congressional Campaign Committee in 2016 and posted sensitive internal campaign documents online, some of the stolen information was later amplified in Republican ads.

Meanwhile, President Donald Trump has not expressed remorse at encouraging Russia to hack into the emails of his 2016 rival, Hillary Clinton, nor has he recanted his praise for WikiLeaks , which released private emails from Clinton's campaign manager John Podesta in an effort to damage her campaign.

With congressional majorities at stake in 2018, US intelligence officials have warned of ongoing efforts by Russia to influence the midterm elections, adding urgency to the question of how campaign committees would treat hacked information.

In the latest version of the bipartisan House campaign pledge, which the DCCC sent back to the NRCC on Tuesday, Democrats suggested adding that "neither committee will use known stolen or hacked information" on top of Republican language to reject "(promoting) or (disseminating) hacked materials to the press, regardless of the source."

Otherwise, the parties seemingly had agreed that they would not "participate, (aid), or encourage hackers or foreign actors in any attempt to influence American elections," nor "seek out stolen or hacked information for use in any operations." The draft document, provided by a source familiar with the latest version of the pledge, further agreed that the committees would report any suspected foreign interference to law enforcement and encourage state officials to safeguard their elections systems.

Protecting "campaigns from outside interference is paramount and must be reflected in the operations of each campaign committee," the draft stated.

Both sides confirmed publicly that they had been close to reaching an agreement on the language of the pledge when the process unraveled this week.

Indeed, Stivers' statement Friday affirming that his committee does not intend to use hacked material was "pretty damn close to the pledge we sent them on Tuesday," said a Democratic source familiar with the negotiations. "I don't know why he wouldn't have just signed it."

For his part, Stivers blamed a Wall Street Journal interview this week in which Lujan said he "would hope that Steve and I are able to roll something out that we agree on this week," adding, "I think that we're close."

Stivers said he saw the comments as the latest attempt by Lujan and Democrats to pressure the NRCC through the media, saying it "was sort of the straw that broke the camel's back on trust."

Democrats have pointed out that the negotiations might never have been public, thus attracting elevated press interest, had Stivers not mentioned the talks during an event in June with the Wall Street Journal and NBC News.

Still, Democrats acknowledged that Stivers' remarks Friday reflected that some progress had been made between the parties, even if it didn't culminate in a signed pact.

"It's rhetoric," the Democratic source said, "but it's rhetoric in the right direction."

While Lujan has consistently called for the committees to designate hacked materials as off-limits, Stivers has been less eager to draw a line in the sand. In June, the Ohio congressman said he would not "run down one of my candidates for using something that's in the public domain."

"Once something is in the public domain, I'm not sure you can say, 'Let's ignore this,' " Stivers said at the time, during the event hosted by the Wall Street Journal and NBC News. "It's out there."

In a statement Friday, as Democrats released their own pledge independent of Republicans, Lujan expressed hope that Stivers might still come around.

"This commitment is important to our democracy, I'm proud to sign it, and it is my hope that the NRCC will ultimately change course and commit to this same pledge," Lujan said.