A new independent poll shows freshman Rep. Rick Berg (R) and former Attorney General Heidi Heitkamp (D) in a virtual tie for the open North Dakota Senate seat.

Heitkamp leads Berg, 47 percent to 46 percent, according to a survey conducted by the Mason-Dixon Polling and Research for KVLY and KFYR television stations. Just 7 percent of voters were undecided in the poll.

The survey comes as good news to Democrats, who hope to keep the seat of retiring Sen. Kent Conrad seat as part of their larger effort to maintain control of the Senate. The results are yet another sign that the race is competitive, although Roll Call continues to rate it as Leans Republican.

Most notably, Heitkamp leads Berg among self-described independent voters, 51 percent to 36 percent.

The survey also shows Berg on track to easily win the GOP nomination against businessman Duane Sand, a frequent statewide candidate, in the Tuesday primary. Berg leads Sand, 73 percent to 16 percent, in the poll.

The survey, taken June 4-6, questioned 625 registered voters who said they were likely to vote in the general election. It had a margin of error of 4 points.