[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2008/POLITICS/11/02/campaign.wrap/art.obama.afp.gi.jpg caption="Sen. Barack Obama tells his supporters they can't 'let up in these next few days.'."]
(CNN) - In the final hours of campaigning, Sen. Barack Obama is urging his supporters to "be my ambassadors" and "close the deal."
In these last three days, we can't afford to slow down or sit back or let up ... not now, not when there's so much at stake," Obama said at a late rally in Springfield, Missouri, his third stop on Saturday.
Sen. John McCain told voters Saturday afternoon that despite being down in the polls, "we're coming back."
"When I see this kind of support, when I see this momentum, when I see this great support, I know we're gong to win," he said in Perkasie, Pennsylvania.
McCain on Sunday was focusing on Pennsylvania, with rallies scheduled in Wallingford and Scranton. Following his Pennsylvania events, he was expected to travel to New Hampshire for a town hall meeting in Peterborough.
Obama leads McCain by 7 points in Pennsylvania, 51 to 44 percent, according to CNN's latest poll of polls. The state has 21 electoral votes at stake.