The main Republican campaign committee is pulling out of a hard-fought race in a southern Arizona swing district.

The National Republican Congressional Committee has canceled its remaining advertising buys in Arizona's 2nd district. That's according to a Republican familiar with the situation who was not authorized to discuss the matter publicly.

The seat represents the Tucson area and was vacated by Republican Rep. Martha McSally so she could run for the state's open Senate seat. The NRCC's exit is a sign of a lack of confidence in the GOP's prospects there.

Former Democratic Rep. Anne Kirkpatrick is running against Republican businesswoman Lea Marquez Peterson for the seat. The district narrowly supported Hillary Clinton in 2016 and was considered one of the most likely to flip in November.