Rep. Rick Berg (R) endorsed Public Service Commissioner Brian Kalk in the competitive GOP primary for the state’s at-large House seat, putting him at odds with some tea-party-affiliated groups.

“Obviously I’m supporting the candidates that were endorsed by the state convention,” Berg said in a wide-ranging interview with Roll Call last week.

Berg is leaving the House after a single term to run for an open Senate seat. A recent poll showed the GOP primary to succeed him is competitive. His endorsement doesn’t come as a big surprise. The state GOP convention also backed Berg for Senate over his primary competition, businessman Duane Sand, a frequent statewide candidate. In endorsing Kalk he’s sticking with the state GOP’s preferred ticket.

But Berg’s endorsement is notable because national conservative groups have rallied behind Kalk’s opponent, Public Services Commissioner Kevin Cramer, in the June 12 GOP primary. Both FreedomWorks and the Club for Growth have endorsed Cramer.

The GOP primary winner will face former state Rep. Pam Gulleson, the presumptive Democratic nominee, in November.

“I think there’s going to be strong support to whoever comes out of the primary election in the House race,” Berg said.

In the general election, Roll Call rates this race as Likely Republican.