[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2008/POLITICS/10/31/last.weekend/art.obamageneric.gi.jpg caption="Sen. Barack Obama is looking to change the Electoral College map."]
WASHINGTON (CNN) - With just days to go before Election Day, Sen. Barack Obama is warning his supporters that things are going to get unpleasant fast - and that the race will come down to every last vote.
"Don't believe for a second this election is over. Don't think for a minute that power concedes anything. It's gonna get nasty, I'm sure, in the next four days," Obama told a crowd in Columbia, Missouri, on Thursday night.
"They will throw everything at us like they've been doing, and we're gonna have to work like our future depends on it in this last week. You know what? Because it does, and every single young person here tonight - I've gotta have every single one of you voting, and you've gotta grab five more, all of you, have gotta vote," he said.
The warning comes after the Illinois senator said in an interview Thursday night that his campaign was winning - some of the most confident language from Obama since he won the Democratic nomination.