NASHVILLE, Tenn. (AP) -- A Davidson County election training session is coming under scrutiny for teaching poll workers to challenge voters they believe may not be U.S. citizens.

Davidson County Election Commissioner Eddie Bryan, a Democrat, told The Tennessean he believed the training was designed to block immigrants from legally voting.

But Republican election officials said it was designed to teach poll workers how to deal with a potential challenge.

Under the state's Challenge the Right to Vote Act, poll workers may ask a voter to take an oath that they have the right to vote. Those refusing the oath cannot vote.

The training last month told poll workers that citizenship requires the ability to read, write and speak basic English, but it noted exceptions for immigrants over 50 and those with impairments.