A crowd of Donald Trump supporters, some armed with rifles and handguns, gathered outside an election centre in Arizona on Wednesday night after unsubstantiated rumours that votes for the Republican president were deliberately not being counted.

Chanting "Stop the steal!", and "Count my vote", the mostly unmasked protesters stood in front of the Maricopa County Elections Department in Phoenix, as Democratic presidential candidate Joe Biden held a razor-thin lead in the critical battleground state...