DES MOINES - Democratic presidential candidate Barack Obama is set to return to Iowa Tuesday, his first trip back to the state since winning the Iowa caucuses in January.

The Obama campaign announced the Illinois senator would hold a rally in downtown Des Moines Tuesday night, calling Iowa a "critical" state that Democrats must win in the November general election.

Presumptive Republican nominee John McCain visited Iowa in recent weeks and has begun running television ads in the state, a signal that Iowa could likely be a battleground state in this year's general election.

Obama's event will be held at the corner of East Sixth and East Locust Streets, with doors opening at 7:30 p.m.

Tickets are not required to the event, but the campaign is encouraging those wanting to attend to RSVP at www.BarackObama.com.

Charlotte Eby can be reached at (515) 243-0138 or chareby@aol.com.