A majority of likely Montana voters, 49 percent, said they’ll vote to re-elect U.S. Sen. Jon Tester, while 39 percent said they favor GOP challenger Matt Rosendale.

The results, released last week, were included in the latest Big Sky Poll conducted by the University of Montana's Social Science Research Laboratory.

While the poll suggests Tester holds a 10 point lead, it adds that roughly 10 percent remain undecided.

“The races are tightening as we approach Election Day,” said UM Professor Sara Rinfret, co-director of the Big Sky Poll. “Compared to our August telephone survey, undecided voters appear to be moving toward the challengers.”

Of those undecided voters, 20 percent said they lean toward Rosendale while 10 percent favor Tester. Six percent of undecided voters favor Libertarian candidate Rick Breckenridge, who garnered 2 percent of the overall poll.

In the race for Montana’s only U.S. House seat, 46 percent of likely voters sided with Democratic candidate Kathleen Williams, while 45 percent said they'd choose freshman Rep. Greg Gianforte.

Of the 7 percent who remain undecided, 17 percent said they lean toward Williams, 3 percent toward Gianforte and 2 percent toward Libertarian candidate Elinor Swanson, who got 2 percent of the poll.

The poll surveyed 607 registered voters between Oct. 10-18. Of those, 533 were classified as likely voters. The survey asked likely voters who they would vote for if the Nov. 6 midterm election were held today.

The margin of error for likely voters is plus or minus 4.33, at a 95 percent confidence level.