Sanders projected to win delegate-rich California

Vermont Senator Bernie Sanders has been projected to win the Democratic primary in California, the "Super Tuesday" state with the largest number of delegates to July's Democratic National Convention (DNC), according to American media reports.

With 88 per cent of the vote in by Thursday night, Sanders was leading with 34.3 per cent of the vote, while former Vice President Joe Biden was in second place with 27.6 per cent, Xinhua news agency quoted NBC News as saying in a report.

Senator Elizabeth Warren of Massachusetts and former New York City Mayor Michael Bloomberg were in third and fourth places, respectively, with 13.3 per cent and 12.9 per cent.

Both of them have dropped out of the race.

California has 415 delegates at stake.

Currently, Sanders picked up 202 delegates from the state to Biden's 148, according to NBC News report.

Despite winning the biggest prize of Super Tuesday's Democratic primaries which took place on march 3, Sanders only grabbed three other states out of 14 voting on that day, trailing behind Biden.

Overall, Biden was leading the two-man race with 848 delegates compared to Sanders with 695, according to NBC News.

To win the Democratic nomination to challenge sitting President Donald Trump, a candidate must receive support from a majority of all the 3,979 pledged delegates on the first ballot of the DNC, which election officials said must be at least 1,991 delegates.

Biden and Sanders will have a face-off in Washington D.C. on Sunday for a Democratic presidential primary debate.

Congresswoman Tulsi Gabbard of Hawaii is still in the Democratic primary race but was trailing well behind Biden and Sanders.

She is not qualified for the Sunday debate.