With less than a week until primary election day, the three Republicans in the Congressional District 1 race are in a dead heat, a new poll shows.

The Remington Research Group poll of 420 likely Republican voters has Andy Tobin with 30 percent of the votes, Adam Kwasman with 29 percent, and Gary Kiehne with 21 percent.

The remaining 20 percent of voters said they still are undecided.

The race is “a true tossup,” said Titus Bond, director of Kansas-based Remington Research Group. He said no one of the candidates can be eliminated as the possible winner based on the poll results.

“It’s going to come down to ground game, turning out their voters,” he said.

The Remington poll is the first independent poll in the race. Candidates haven’t released the results of their own internal polls.

Kwasman and Tobin have robo-calls going out to voters from trusted Republican leaders. Maricopa County Sheriff Joe Arpaio recorded a call for Kwasman and Mitt Romney recorded a call for Tobin.

The Kwasman and Kiehne campaigns are using volunteers to make phone calls to voters in key areas to encourage people to vote.

Tobin spokesman Bill Cortese said fliers are hitting mailboxes and Tobin is traveling and promoting his conservative record.

Tobin’s campaign has gotten a flood of last-minute help with ad buys from outside conservative groups including Preserve America’s Future and Main Street Advocacy.

Both Kwasman and Kiehne characterized that cash as a bailout from establishment Republicans and said it’s a sign Tobin’s campaign isn’t going well.

Kiehne spokesman Chris Baker called the Remington poll a joke and said it’s “not worth the paper it’s printed on.”

Contact reporter Becky Pallack at bpallack@tucson.com or 573-4251. On Twitter: @BeckyPallack