Editor's note: This story has been updated with comment from Karl Rove's chief of staff.

U.S. Sen. Ted Cruz is digging in his heels in an increasingly bitter spat with Karl Rove, a longtime adviser to Texas' most famous family in politics — a family now fielding former Florida Gov. Jeb Bush against Cruz in the 2016 presidential race.

The war of words, which comes on the eve of a tour to promote Cruz's upcoming book, centers on former President George H.W. Bush's support for Cruz in the state attorney general's race in 2009. Cruz, who was fresh off of a stint as the solicitor general of Texas, made a bid for the statewide post but abandoned it when it became clear his boss, then-Attorney General Greg Abbott, was running for re-election.

Late Sunday, Cruz's presidential campaign released emails appearing to back up a claim in his book that Rove wanted Cruz to keep quiet about a donation from George H.W. Bush.

By Cruz's telling — which Rove has denied — that was because Rove was raising money for George W. Bush's presidential library in Dallas, and major donors were backing someone else for attorney general. The other contender was believed to be then-state Rep. Dan Branch, a Dallas Republican and Jeb Bush backer who ultimately chose not to run for the office until 2013.

"I appreciate your doing what you can to keep this down — the distress you mention is not mine or 43 — it is the people raising money for the library who are also Branch fans and will not understand why one part of the Bush family is for not-the-guy while they are raising money big bucks for library," Rove wrote Cruz, according to the emails provided by Cruz's campaign.

Rove does not have a record or recollection of that email, according to his office. Kristin Davison, Rove's chief of staff, said Monday that Rove does have a record of another email Cruz released, one in which Cruz asks George H.W. Bush's assistant to withhold any further advertisement of the former president's support, citing concerns from Rove that it would "put President Bush 43 in a difficult position." That email, Davison said, "confirms Karl's account that their phone call in 2009 was about involving President Bush 41 in a primary where the sitting state attorney general had not made a final decision."

After Cruz met with George H.W. Bush about an endorsement, Rove was "irate," and asked Cruz to return the donation, which Cruz did not do, according to an excerpt from Cruz's book, titled A Time for Truth, that was provided to the conservative news site Breitbart. Rove, Cruz wrote in the excerpt, "suggested that the elder Bush was too old to have good judgment anymore." By Cruz's account, Rove implied he would have another former president, George W. Bush, endorse Cruz's opponent in the attorney general's race if Cruz further spread the word about his support from George H.W. Bush. The emails the Cruz campaign released didn't address this aspect of Cruz's book.

After the excerpt was published Sunday morning, Rove denied each of Cruz’s accusations point by point in a blog post.



"I am accustomed to being criticized for others’ political benefit, but am disappointed in how Senator Cruz decided to raise the name of one of the finest presidents our country has ever known, President George H.W. Bush,” Rove wrote.

Rove also used the blog post to fit in a fresh jab at Cruz, while discussing how the ambitious politician continued to rely on Rove's counsel as he campaigned for U.S. Senate in 2012.

"One piece of advice I offered was that he should stop describing himself as the 'next Marco Rubio,' since he did not have Senator Rubio’s outstanding legislative record of accomplishments as speaker of the Florida House of Representatives," Rove wrote.

Late Sunday, Cruz's campaign circulated the emails to reporters along with a statement from Cruz expressing surprise at Rove's response.

“I have known Karl Rove for a long time, and have considered him a friend," Cruz said. "I understood that my recounting ... the threats he made in the 2009 Texas Attorney General race — and the disparaging remarks he made about President George H.W. Bush — would cause him some discomfort."

“But I never imagined that his response would be a straight-out falsehood," Cruz added. "It’s disappointing; this is why people are so cynical about politics, because too many people are willing to lie."

Cruz's book goes on sale Tuesday, and he is expected to travel across the country promoting it, including to Houston on the release date.

The episode is likely to shine a new light on Cruz’s relationship with the Bushes as Cruz positions himself as the most conservative foe of Jeb Bush in the 2016 race. Before becoming solicitor general, Cruz worked on George W. Bush's presidential campaign, then for the Federal Trade Commission and the U.S. Department of Justice while Bush was president.