Republican presidential candidate Ben CarsonBenjamin (Ben) Solomon CarsonCarson's affordable housing idea drawing undue flak Overnight Energy: Trump EPA looks to change air pollution permit process | GOP senators propose easing Obama water rule | Green group sues EPA over lead dust rules Green group sues EPA over lead dust rules it says are too lax MORE is warning rival Ted CruzRafael (Ted) Edward CruzIs this any way for NASA to build a lunar lander? GOP strategist predicts Biden will win nomination, cites fundraising strength 3 real problems Republicans need to address to win in 2020 MORE that he must hold his campaign staff accountable for suggesting the retired neurosurgeon was dropping out of the 2016 race. 

"I call on Senator Cruz to take decisive action at a senior level within his campaign or I fear this culture of destructive behavior will only continue," Carson said in a fundraising email Thursday evening. 
 
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The escalation of the ongoing fallout between Cruz and Carson comes after Breitbart News published a voicemail received by a Cruz precinct captain in Iowa on the night of the Iowa caucus that told her to "tell any Ben Carson voters that for tonight, uh, that they not waste a vote on Ben Carson, and vote for Ted Cruz." 
 
A second voicemail said Carson was suspending his campaign. 
 
The voicemails, which were left at 7:07 p.m. and 7:29 p.m., according to Breitbart, came after Carson's campaign had clarified that while he was returning to Florida briefly, he was not dropping out of the 2016 election. 
 
Referring to a frequent campaign slogan from Cruz, Carson added on Thursday that "if Senator Cruz truly wants to defeat the Washington Cartel, he must be willing to hold people accountable for adopting deceptive Cartel tactics."
 
Carson's comments, and the Cruz campaign voicemail, are the latest in an escalating battle between the two. 
 
Carson has repeatedly accused Cruz's campaign of spreading rumors during the Iowa caucuses that the retired neurosurgeon was quitting the presidential race, suggesting the Texas Republican negatively impacted his campaign.
 
Cruz's campaign has defended itself, saying it was only sharing news reports. 
 
Catherine Frazier, a spokeswoman for Cruz's campaign, doubled down Thursday, telling Breitbart that "the voicemails are in line with the reports that were made at that time."