OKLAHOMA CITY (AP) - Early voting began today for voters casting ballots in Oklahoma's primary runoff election.

The top race is in the 2nd Congressional District, where two Republicans and two Democrats are vying for their parties' nominations. That seat is being vacated by Democratic congressman Dan Boren, who is not seeking re-election.

In counties with a state or federal office on the ballot, voters can cast absentee ballots in person at their county election board office from 8 a.m. to 6 p.m. on Friday and Monday, and from 8 a.m. to 1 p.m. on Saturday. In counties with only local or county races, election board offices will not be open for early voting on Saturday.

Individual polling places will be open from 7 a.m. to 7 p.m. on Tuesday.