Two U.S. Border Patrol (CBP) vehicles briefly parked outside an early voting site in Leon County, Florida, prompting the county’s elections supervisor to file a formal complaint with the FBI, a local official said.

The vehicles arrived outside the county’s busiest early voting site of Northeast Branch Library in Tallahassee about 10:15 a.m. on Monday, shortly after early voting began, according to Leon County Supervisor of Elections Mark S. Earley.

"The two vehicles appeared to stay for approximately 10 minutes before leaving the vicinity of the site," Earley said. "It is worth noting that we did not receive any calls from voters regarding the incident. "Since learning of this, I have been in close communication with our local, state, and federal partners to make sure they are aware of this issue. I have lodged a formal complaint with the FBI, and to their credit, they are taking this seriously."

Newsweek contacted CBP, the Department of Homeland Security, the FBI and Earley’s office for comment via email outside regular business hours on Thursday.

In a separate incident in Monroe County, Supervisor of Elections Sherri Hodies told Keys News Talk that her office was investigating after federal immigration agents were seen near an early voting location in Key Largo. Hodies said several voters contacted her office expressing concern about the agents’ presence, with some describing it as voter intimidation or interference.

Video showed federal immigration agents stopping a vehicle near the entrance to the Murray Nelson Government Center, according to WPLG. Hodies said officials were trying to determine whether the stop took place outside the polling location or whether the location was intentional.

Federal law prohibits federal officials from deploying armed personnel to polling places, except when needed to repel armed enemies of the United States.

Yet concerns have been raised over the prospect of federal immigration agents, such as Immigration and Customs Enforcement (ICE) and U.S. Customs and Border Protection (CBP), being deployed to polling stations during the midterms.

The Trump administration said it has no plan for federal agents to patrol polling places, but President Donald Trump, Homeland Security Secretary Markwayne Mullin and FBI Director Kash Patel have all declined to rule it out.

Patel told lawmakers on September 15 during a Senate Judiciary Committee hearing that agents would go to a polling place if there were a suspected violation of the law, saying: “On Election Day, the FBI will follow the law. If there’s a reason to go there because there’s been a violation of law, we will. Otherwise we won’t.”

Earley said he contacted local, state, and federal officials after learning about the vehicles and filed a formal complaint with the FBI.

"Voters should never experience intimidation from anyone when they are voting, and that includes being intimidated by law enforcement or any other governmental officials," Earley said in a press release.

Under the Trump administration’s mass deportation drive, CBP has worked alongside Immigration and Customs Enforcement (ICE) on the front lines of the administration’s crackdown on illegal immigration.

Trump ally and former White House strategist Steve Bannon has repeatedly called for ICE agents to be at polling places during this year's midterm elections. Bobby Charles, the Republican nominee for governor of Maine, has also called for federal agents at polling places, saying in August that he intended to ask White House border czar Tom Homan to send ICE agents and U.S. marshals to voting sites ahead of the midterms, according to audio obtained by the Associated Press.

A DHS official previously told Newsweek: "ICE is not planning operations targeting polling locations. ICE conducts intelligence-driven targeted enforcement, and if an active public safety threat endangered a polling location, they may be arrested as a result of that targeted enforcement action."