U.S. election offices have been forced to tighten security in response to a deluge of threats and intimidating behaviour by conspiracy theorists.

In Jefferson County, Colorado, security guards will be stationed outside the busiest polling centres on Election Day.

In Flagstaff, Arizona, voters will encounter bulletproof glass and need to press a buzzer to enter the election office.

And in Tallahassee, Florida, election workers will count ballots in a building that has been reinforced with walls made of the super-strong fibre, Kevlar.

These measures are just a few of the ways in which elections officials are beefing up security ahead of the midterms.

But in some states, elections offices are struggling to find the money to pay for basic security measures, let alone more sophisticated ones.

It comes as one in five election workers reveal they will not continue in their jobs come the 2024 Presidential election amid safety fears.