Story highlights Top Republican officials are gathered at a Koch brothers donor conference

The Koch brothers are sitting out the presidential race

Colorado Springs (CNN) The powerful political network helmed by Charles and David Koch is ruling out running advertisements intended to hurt Hillary Clinton, another sign of their insistence on avoiding the presidential race.

The Koch network has previously said they will not back Republican candidate Donald Trump, but on Saturday officials told reporters that they would not run negative Clinton spots, a position taken by some Republican groups that are uneasy with the controversial GOP standard-bearer. The group is laser-focused on maintaining and expanding the Senate majority -- in the midst of a $42 million television advertising campaign focused on a half-dozen states -- and would only use Clinton to bash Senate Democratic hopefuls.

Network officials outlined their plans here as 400 of their donors prepared to hear from a roster of Republican leaders. House Speaker Paul Ryan is among the politicians who scored invites to one of the nation's most sought-after political retreats at a lavish campus nestled in the Rocky Mountains.

Ryan will be joined here at the summit hosted by the Freedom Partners Chamber of Commerce alongside up-and-coming Republicans like Senators Cory Gardner of Colorado, Tim Scott of South Carolina, and Mike Lee of Utah, Koch spokesman James Davis said Saturday. Other speakers will include Senate Majority Whip John Cornyn of Texas, Kentucky Gov. Matt Bevin, Rep. Jason Chaffetz of Utah and Rep. Mike Coffman of Colorado.

The Koch network is sitting out of the presidential campaign entirely, a blow to Trump's presidential ambitions. Trump claimed in a tweet Saturday that he declined a meeting request from Charles and David Koch this weekend, though Koch officials say that they were not aware of any contact with him on Friday when both the Kochs and Trump coincidentally were in Colorado Springs at the same time.

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