Bomb threats have been reported in several swing states that are key in the US presidential election, causing delays in the closing of polls.
The FBI is working with local law enforcement and officials in four states, CNN was told.
Swing states, that is, those in which the situation is uncertain, are Georgia, North Carolina, Wisconsin, Pennsylvania, Nevada, Arizona and Michigan. All the rest, according to polls, overwhelmingly favor Democrats or Republicans.
The states that received these threats - Michigan, Wisconsin, Arizona and Georgia - evacuated polling places because of the threats, some of which, according to the FBI's previous information, were sent from Russian e-mail domains and were judged to be frivolous.
In Pennsylvania, a bomb threat prompted the evacuation of a government building in West Chester, where voting services are located, said Josh Maxwell, chairman of the Chester County Board of Elections.
The building is currently being searched by dogs and will be reopened for voting if nothing is found, Maxwell wrote on social media.
Additionally, a Pennsylvania judge extended voting hours in Clearfield County until 21 p.m. ET after a bomb threat was made at the Clearfield County Administration Building, where votes were counted.
Clearfield County is located northeast of Pittsburgh.
Several bomb threats in Michigan and Georgia caused voting delays as security officials cleared the sites. Twelve polling places in Georgia extended their hours due to bomb threats, according to Secretary of State Brad Raffensperger, as well as an additional three locations for "routine reasons."
Wisconsin also received threats that a US official said were aimed at disrupting the vote.
Navajo County, Arizona, also received "unconfirmed" bomb threats at four locations, and state officials believe the threats originated in Russia, Arizona Secretary of State Adrian Fontes said.
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