The campaign chief for Democrat Barack Obama has said the battle against Hillary Clinton for the party's presidential nomination will soon be over.

David Axelrod said Sunday the party is coming to the end of the process. Axelrod said Obama will continue to collect endorsements in coming days from the superdelegates who are likely to decide the race.

Clinton's senior advisor, Howard Wolfson, has rejected the idea that the campaign is over. Wolfson said Clinton is determined to campaign until early June when the last of six remaining statewide nominating contests is held.

Obama has overtaken Clinton in many tallies of superdelegates, party insiders who are free to vote for either candidate at the party's nominating convention in August.

There is no official count of superdelegate support. They are being compiled by various news organizations, and some counts still show Clinton with a slim lead.

Clinton campaigned Sunday in West Virginia, which holds its primary election Tuesday. Voter surveys say she is likely to carry the state.

Obama took a day off from campaigning. He spent Sunday with his family in Chicago.

Some information for this report was provided by AP, Bloomberg and Reuters.