Trump said, "No, I think it's rigged against Bernie.
But I think he'll pull it through.
It was rigged against me four years ago and I pulled it through.
I think it's rigged against Bernie.
You see what's happening with Klobuchar.
I heard just something happened there." Five candidates remain in the running for the nomination to take on Republican President Donald Trump in November's election, down from more than 20 earlier in the campaign.
Former New York City Mayor Michael Bloomberg and former Vice President Joe Biden have emerged as the main contenders for the votes of moderate Democrats, while Sanders is the progressive front-runner nationally, eclipsing Senator Elizabeth Warren.