Utah Sen. Orrin Hatch (R) is fending off an early surge by his junior House upstart, Rep. Jason Chaffetz (R), claiming the House member pledged not to run against him in 2012.

Hatch is disputing Chaffetz's version of a conversation the two had in Hatch's office in 2009, when Hatch alleged Chaffetz promised not to challenge him for re-election. Hatch is up for a seventh term in 2012.

"Jason has been with me right in my office and said that he's not going to run against me, and made it very, very clear," Hatch said during a Friday interview with KCPW, a National Public Radio affiliate with a base in Salt Lake City.

Chaffetz denies the pledge, and says he only pledged to run for his current re-election, according to the Salt Lake Tribune.

"I have no idea what he's thinking about," Chaffetz said of Hatch. "I told him I wasn't going to run against Bob Bennett. Wrong senator."

Bennett, Utah's junior senator, lost his bid for reelection this year at the state party's nominating convention.

A Hatch spokeswoman later said Chaffetz's pledge "isn't up for interpretation."

"Senator Hatch takes very seriously the principle of keeping his word. Of course, I suppose Jason can break it any time he wants to. Let's leave it at that," said spokeswoman Heather Barney.