"Please think through this decision. It is not a wise decision," Clinton said to applause.
"Every time we have a vigorous contest like we're having this primary election, people get intense. Senator Obama has intense support. I have intense support. It's exciting because people want to be involved. But, the differences ... pale in comparison to the differences between us and Senator McCain."
North Carolina holds its primary May 5, with 115 delegates at stake.
Obama made a similar point Thursday in an interview on ABC's "World News."
"There are going to be some bruised feelings, whoever the nominee is. We are going to have to come together and remind ourselves that there is a heck of a lot bigger difference between either Senator Clinton or myself, and John McCain," Obama said.
He said the protracted contest would not harm the party in the long run.
"I think short term, there is going to be work to do for the nominee to bring the party back together again. People feel pretty passionate about their respective candidates. I appreciate that, and I understand it," Obama said.
The former first lady, who trails Obama in the popular vote and in pledged delegates, has pushed back on critics who argue that she should cease her criticisms of the Illinois senator and end her campaign so he can focus on defeating McCain.
Clinton pledged Thursday to be a team player no matter the outcome of the primary contest.
"I intend to do everything I can to make sure we have a unified Democratic Party," she said. "When this contest is over and we have a nominee, we're going to close ranks. We're going to be united ... The most important goal for us is to put a Democrat back in the White House."
Even Al Gore, the former vice president and 2000 Democratic nominee, professed no urgency to resolving the contest in an interview with The Associated Press.
"What have we got, five months left?" he said, when asked about whether he would make an endorsement soon.
When pressed on whether the nominee could be decided before the national convention in August, Gore said: "I think it's going to resolve itself. But we'll see."
