HARRISBURG, Pa. -- US Democratic Sen. Hillary Rodham Clinton accused rival Sen. Barack Obama and his allies of trying to stop people from voting as some of his backers have called on her to drop out of the presidential race. The Obama campaign rejected the charge, dismissing Clinton's criticism as "completely laughable."

US Democratic presidential hopeful, Sen. Hillary Rodham Clinton, D-NY, speaks to truck drivers protesting the  price of fuel outside of the Capitol Diner in Harrisburg, Pa., Monday, March 31, 2008. [Agencies]

In a series of television interviews in states holding upcoming contests, Clinton vowed to press on with her campaign and suggested Obama and his supporters wanted to keep those states from playing a role in selecting the party's presidential nominee.

"My take on it is a lot of Senator Obama's supporters want to end this race because they don't want people to keep voting," she told CBS affiliate KTVQ in Billings, Mont. "That's just the opposite of what I believe. We want people to vote. I want the people of Montana to vote, don't you?"

Montana holds its primary June 3. The New York senator made similar comments in interviews with stations in Indiana and North Carolina, which hold primaries May 6.

Obama leads the overall race for the Democratic nomination with 1,631 delegates, including separately chosen party and elected officials known as superdelegates. He got the backing of Minnesota Sen. Amy Klobuchar on Monday. Clinton has 1,501, according to the latest AP tally.

Clinton almost certainly will end the primary season narrowly trailing Obama in the popular vote and among pledged delegates unless the nullified primaries in Florida and Michigan are counted -- an unlikely scenario at best. But Obama is unlikely to end the race with the 2,024 pledged delegates needed to win outright either, meaning the nominee will be determined by roughly 800 superdelegates.

Responding to Clinton, Obama spokesman Bill Burton said: "That is completely laughable from a campaign that thought the race would be over on February 5. We have encouraged our supporters to do no such thing and Senator Obama was very clear he supports her carrying on in this race."

Vermont Sen. Patrick Leahy last week became the first leading Democrat to openly call on Clinton to step aside and cede the nomination to Obama. He said he worried the prolonged nominating battle was strengthening the chances of the Republican nominee in waiting, John McCain.

Since then, Obama and his supporters have said Clinton should stay in the race as long as she chooses while indicating a lengthy primary battle would not help the party's position in the general election.

Obama has been picking up superdelegates at a rapid clip while Clinton's success with that group has slowed considerably.

"I don't even keep track of it, I can't even tell you that figure," Clinton said when asked by Pittsburgh CBS affiliate KDKA how many superdelegates had endorsed her in recent weeks.

As she spoke, her husband, former President Clinton, was in Oregon, lobbying uncommitted superdelegates.