An influential conservative super PAC slammed Republican Karen Handel as a "big-spending career politician" in a debut TV ad in support of one of her top GOP rivals.

The spot from Club for Growth, which has endorsed Bob Gray in the April 18 election, is first overtly Republican-on-Republican attack ad in Georgia's special election. The group had telegraphed the coming attack days ago in a memo.

It spotlights several controversies from her stint as Fulton County Commission chair, including a budget vote to spend nearly $2 million “planting trees to beautify government properties.”

“Stop Karen Handel," the narrator intoned, "a big-spending career politician that we can’t trust with our money.”

Handel, a former Georgia secretary of state, is the top Republican in many of the polls despite spending no campaign cash yet on TV advertising. But Club for Growth's attack ad could force her to counter quickly in the crowded 18-candidate contest. Handel's campaign didn't immediately comment.

With analysts conceding a spot in the likely June 20 runoff to Democrat Jon Ossoff, Republicans are escalating their fight for the other spot. Former state Sens. Judson Hill and Dan Moody are also ratcheting up their campaigns.

Read more: Republicans escalate wars with each other in Georgia special election