Washington: Hillary Clinton's Pennsylvania win has bought her time - but not much - to make her case to the Democratic Party's superdelegates, many of whom expressed a strong desire on Wednesday to end the nominating contest once the final votes are cast.

While few seem eager to use their power to call a halt to the presidential race - and many said they welcomed the continued balloting - a number of party leaders and other activists sent a clear signal that they want the fight over well before the Democratic convention in August.

"If June 3 is the last primary, then after June 3 is the time to make a decision," said Wayne Dowdy, chairman of the Mississippi Democratic Party and an uncommitted superdelegate.

Blake Johnson, vice chairman of Alaska's Democratic Party, agreed. "After all the states have voted, it'll be time for the superdelegates to make their decision," said Johnson, who is also neutral in the primaries.

Interviews with dozens of superdelegates on Wednesday turned up a growing acceptance that the intramural contest between Senator Clinton of New York and Senator Barack Obama of Illinois probably will continue for another six weeks. The primary season ends June 3 in Montana and South Dakota.

Many viewed the ongoing race as a good thing, toughening the eventual nominee and giving Democrats in more states a chance to organise and get involved. The next contests are May 6 in North Carolina and Indiana.