Panic buttons for poll workers, special weapons teams deployed on rooftops, and hundreds of National Guard personnel on standby.
The 2024 US presidential campaign has been a particularly volatile one, and security for Election Day on Tuesday is being ramped up to unprecedented levels given concerns over possible civil unrest, election chicanery, or violence against election workers.
The states of Oregon, Washington and Nevada have activated the National Guard -- and the Pentagon says at least 17 states have placed a total of 600 National Guard troops on standby if needed.
The FBI has set up a national election command post in Washington to monitor threats 24 hours a day through election week, and security has been bolstered at many of the nearly 100,000 US polling stations.
Nineteen states have enacted election security enhancement laws since 2020, the National Conference of State Legislatures says.
With Democrat Kamala Harris and Republican Donald Trump deadlocked at the climax of the 2024 race, authorities are keen to reassure jittery Americans that their votes are secure. But they are also bolstering physical security for election operations nationwide.
Runbeck Election Services, which provides security technology for poll operations, confirmed to AFP Monday it has ordered some 1,000 panic buttons for clients that include election facilities and their workers.
These small devices, worn as a lanyard or held in a pocket, are paired with a user's cell phone and contact law enforcement or other authorities in case of emergency.
Officials in the seven key swing states are eager to convey confidence in a secure and fair election.
"Here in Georgia, it is easy to vote and hard to cheat. Our systems are secure and our people are ready," Georgia Secretary of State Brad Raffensperger told reporters on Monday.
Fringe activists might bring some "extra drama" to the proceedings, he said.
But Raffensperger added he expects the election to be safe in Georgia, where Trump faces criminal charges over his interference in the 2020 election.
In Arizona, a southwestern swing state that became a fulcrum of election night unrest and conspiracy theories that year, officials have turned the state's main election and ballot counting facility, in Maricopa County, into a veritable fortress.
It now has wrought-iron fencing, barbed wire, armed guards and a SWAT presence on the roof, according to officials.
"Since January of 2021, our office has increased badge security access, installed permanent barriers, and added additional cybersecurity measures based on the recommendations of law enforcement and other experts," Taylor Kinnerup, communications director for the Maricopa County Recorder's Office, told AFP on Monday.
Pennsylvania's Department of State, which oversees elections in the nation's largest swing state, said its preparation includes defenses of infrastructure and partnerships with security and law enforcement agencies, although it did not provide details.
The new layers of security follow the election chaos from 2020, particularly after Trump supporters stormed the US Capitol building on January 6, 2021 aiming to halt certification of the election results that confirmed Joe Biden as the winner.
Officials are also warning of major cyber and hacking threats, particularly from abroad.
Russia, Iran and China are conducting influence operations to undermine American confidence in election legitimacy and "stoke partisan discord," Cybersecurity and Infrastructure Security Agency director Jen Easterly recently told NBC News.
This "firehose of disinformation," she added, is "creating very real physical threats to election workers."
Meanwhile in Washington, high metal fencing has been erected around the vice president's residence and the White House, and some shopfronts have been boarded up.
"There will be no tolerance for violence in our city," DC Police Chief Pamela Smith told reporters Monday.
"Should it require additional time to know the results of this election, we want everyone to know that we are ready to handle many different scenarios, and we have the right people in place to keep our city safe," she said.
