JOE Biden has swept to victory in Florida, Illinois and Arizona, increasingly pulling away with a Democratic presidential primary upended by Covid-19.

Biden’s clean sweep also built further pressure on his only rival Bernie Sanders to abandon his campaign.

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

Biden’s trio of wins doubled his delegate haul over Sanders, giving him a nearly insurmountable lead.

Sanders’ campaign manager said yesterday he “is going to be having conversations with supporters to assess his campaign”, but suggested Sanders is in “no hurry to make any decisions about leaving the race”.

Top Democratic leaders and donors have increasingly lined up behind Biden as the best option to square off against President Donald Trump in November.

Using a livestream to address supporters from his home state of Delaware, Biden seemed ready to move past the primary. He paid tribute to Vermont senator Sanders for advancing key issues like affordable health care and combating climate change.

“Senator Sanders and his supporters have brought a remarkable passion and tenacity to all of these issues. Together they have shifted the fundamental conversation in this country,” Biden said. “So let me say, especially to the young voters who have been inspired by Senator Sanders: I hear you, I know what’s at stake, I know what we have to do.”