Incumbent Sen. Kay Hagan, D-N.C., leads all potential Republican challengers by double digits in a poll released Tuesday.

The survey, conducted by PPP, is an encouraging sign for Hagan, who is considered among the most vulnerable Democrats seeking reelection in 2014. Notably, the results show Hagan's support growing since last month, when she bested her closest potential challengers by 8 percentage points in a separate PPP poll.

The new poll showed 43 percent of voters hold a favorable view of Hagan's job performance.

Republicans have yet to coalesce around a challenger for Hagan. Some potential candidates have been testing the waters for a bid, including state Sen. Phil Berger, who this week released a campaign-style television attack ad and on Tuesday attacked Hagan in a press release for supporting the president on Syria.

Berger performed comparably against Hagan to a number of other potential Republican candidates, including Thom Tillis, a state representative who is reportedly considering entering the race.