PHOENIX (AP) — Most Arizona voters have already cast their primary election ballots early but polling places are open for election-day voting Tuesday.

Polls opened at 6 a.m. and are scheduled to remain open until 7 p.m.

Voters are choosing party nominees for one of the state's two U.S. Senate seats, nine U.S. House seats, governor and other state offices.

No incumbents are on the ballot in two U.S. House races because the current officeholders are running for the Senate seat now held by Republican Jeff Flake, who is not running for re-election.

The state's other Senate seat is vacant with Sen. John McCain's death Saturday. Gov. Doug Ducey will appoint a replacement to serve the next two years.