LITTLE ROCK, Ark. (AP) - Arkansas' revived law requiring voters to show photo identification before casting a ballot will be put to the test as soon as it takes effect this week, with early voting beginning for five local sales tax elections.

Voters heading to the polls early in three cities and two counties Tuesday for special elections on sales tax measures will be required to show photo ID before casting a ballot, or sign a sworn statement confirming their identity under the law approved by the Legislature earlier this year. The measure revives a similar voter ID restriction that was struck down by the state's highest court three years ago.

The American Civil Liberties Union says it's watching the enforcement to prepare for a potential lawsuit if voters are disenfranchised.