Joe Biden swept to victory in Florida, Illinois and Arizona, increasingly pulling away with a Democratic presidential primary upended by the Coronavirus and building pressure on Bernie Sanders to abandon his campaign.

The former vice president's third big night in as many weeks came Tuesday amid tremendous uncertainty as the Democratic contest collides with efforts to slow the spread of the virus that has shut down large swaths of American life. Polls were shuttered in Ohio, and although balloting went ahead as scheduled in the three other states, election workers and voters reported problems.