Democratic US presidential candidate Bernie Sanders speaks during a campaign rally in Cloverdale, California, US June 3, 2016. [Photo/Agencies]

WASHINGTON - As US mainstream media were about to call the race for Democratic presidential candidate Hillary Clinton on next Tuesday, Bernie Sanders, Clinton's rival in the nomination race, said otherwise.

"The media is in error when they lump superdelegates with pledged delegates," said Sanders at a press conference on Saturday in Los Angeles, California. "Hillary Clinton will not have the requisite number of pledged delegates to win the Democratic nomination at the end of the nominating process on June 14."

Vowing to continue his fight for nomination beyond the primary season, Sanders predicted that the Democratic National Convention "will be a contested convention."

As of Saturday, Clinton led Sanders in pledged delegates count with 1,769 to 1,501, according to the latest New York Times tally.

To win the party nomination, any candidate needs 2,383 delegates in total.

While Clinton was widely viewed as unlikely to expand her pledged delegates over the threshold of 2,383 next Tuesday, when six of the remaining seven Democratic nomination races will be held, US cable news, such as CNN, had already predicted that she would clinch the nomination soon with the help of unpledged delegates, or superdelegates.

In an earlier TV program broadcasted in late May, MSNBC host Chris Matthews also revealed that major US TV networks were planning to call the Democratic primary for Clinton on June 7, hours before the close of polls in California.

"I'm told by the experts on numbers around here are NBC and elsewhere that come June... that at 8 o'clock that night, Eastern time, the networks will be prepared, including this one, to announce that Hillary Clinton had now gotten over the top, that she will have won the nomination in number, it's done," said Matthews then to Sanders' campaign manager Jeff Weaver.