A new 8 News NOW poll shows a widening gap in the U.S. Senate race, but also a growing group of undecided voters.

The poll of Nevada voters, conducted earlier this week, shows Democrat Catherine Cortez Masto with a five percent lead over Republican Rep. Joe Heck. The hotly-contested race will decide who fills the U.S. Senate seat left open after longtime Democratic Senator Harry Reid retires.

The 8 News NOW poll, done by JMC Analytics and Polling, shows 40 percent say they would vote for Masto if the election were held today, while 35 percent said they would vote for Heck.

The margin of error is four percent.

Question 3: If the election for U.S. Senate were held today, which candidate would you support? (Party affiliations of candidates mentioned) Cortez Masto 40%

Heck 35%

Jones 3%

Gumina 2%

Sawyer 1%

Williams < 1%

None of the above 4%

Undecided (Not read) 16%

Of those who selected Undecided, the poll shows most are leaning in the direction of Cortez Masto.

Question 4: (Only if “undecided” is selected for the previous question) Given that you are undecided, which candidate are you leaning towards supporting? (Party affiliations of candidates mentioned) Cortez Masto 41%

Heck 36%

Jones 3%

Gumina 2%

Sawyer 1%

Williams <1%

None of the above 5%

Undecided (Not read) 14%