Democratic challenger edges further ahead in Arizona Senate race: Reuters/Ipsos poll

Democratic candidate for the U.S. Senate Gideon casts her ballot at the town hall in Freeport

By Jason Lange

WASHINGTON (Reuters) - Democratic U.S. Senate candidate Mark Kelly pulled further ahead of Arizona Republican incumbent Martha McSally, a Reuters/Ipsos poll showed on Wednesday, ratcheting up the risk to Republicans of losing control of the Senate in the Nov. 3 elections.

There are about 12 competitive U.S. Senate races this year, 10 with vulnerable Republican incumbents and two with vulnerable Democrats. To have a majority in the Senate, Democrats need to pick up three seats if the party wins the White House, which gives the vice president a tie-breaking vote, and four if not.

Here are the latest results on three Senate races on which Reuters/Ipsos is polling:

ARIZONA (Oct. 7-14 poll)

* Voting for Democratic challenger and former astronaut Mark Kelly: 52%

* Voting for Republican Senator Martha McSally: 41%

* Kelly was up 51%-41% in the prior poll.

* 10% say they had already voted.

NORTH CAROLINA (Oct. 7-13 poll)

* Voting for Democratic challenger Cal Cunningham: 46%

* Voting for Republican Senator Thom Tillis: 42%

* Cunningham led Tillis 47%-42% in the prior week.

* 12% said they had already voted.

MICHIGAN (Oct. 7-13 poll)

* Voting for Democratic Senator Gary Peters: 52%

* Voting for Republican challenger John James: 44%

* Peters led James 50%-43% in the prior week.

* 22% said they had already voted.

NOTES: The Reuters/Ipsos poll was conducted online and in English. The Arizona survey included 667 likely voters and had a credibility interval of 4 percentage points. The earlier Michigan poll surveyed 620 likely voters and had a credibility interval of 5 percentage points. North Carolina's surveyed 660 likely voters and had a credibility interval of 4 percentage points.

(Reporting by Jason Lange; Editing by Scott Malone and Peter Cooney)