Vehicles with Trump flags halted traffic on Sunday on the Garden State Parkway in New Jersey and jammed the Mario M Cuomo Bridge between Tarrytown and Nyack, New York.
Another pro-Trump convoy in Virginia ended in a tense shouting match with protesters as it approached a statue of Robert E Lee in Richmond, reports the New York Times.
In Georgia, a rally for Democrats was canceled shortly before it was scheduled to begin on Sunday, with organizers worried about what they feared would be a "large militia presence" drawn by President Trump's own event nearby.
As America races toward Election Day, the tensions and acrimony surrounding an extraordinarily divisive campaign, coming on the heels of a summer of protests and racial unrest, are bleeding into everyday life and adding further uncertainty to an electoral process in which Trump has not committed to a peaceful transfer of power.
The incidents came a day after a group of Trump supporters in Texas, driving trucks and waving Trump flags, surrounded and slowed a Biden-Harris campaign bus as it drove on Interstate 35, leading to the cancellation of two planned rallies.
The FBI confirmed on Sunday that it was investigating the incident.
On Saturday, President Trump tweeted a video of the incident with a message, "I love Texas!"
After the FBI announced it was investigating, he tweeted again, saying: "In my opinion, these patriots did nothing wrong," and instead "the FBI & Justice should be investigating the terrorists, anarchists, and agitators of ANTIFA."
In Graham, NC, a get-out-the vote rally on Saturday ended with police using pepper spray on some participants, including young children, and making numerous arrests. Organizers of the rally called it flagrant voter suppression.
"These people are afraid," the Rev. Gregory B Drumwright, his eyes still burning, said as he assailed the police action in Graham.
"There's a climate of fear around this."
Those were just the incidents that were caught on video. Kristen Clarke executive director of the Lawyers' Committee for Civil Rights Under Law, a voting rights group, said there had been many more. The group settled a lawsuit last month against officials in Graham who they accused of violating the First Amendment rights of protesters.
"We are very concerned about groups lurking and trying to intimidate voters in particular communities," Clarke said.
Her group's election protection hotline received calls from nearly a dozen counties in Florida just over the past week, she said, reporting individuals or groups harassing voters at the polls.
"We want voters to know these sporadic incidents are being addressed, and we want them to be able to cast their ballot," Clarke added.
Law enforcement authorities are increasingly worried, too — not just about what they have already seen, but also about what has been threatened, especially online.
Most of the internet threats have not migrated to the nation's streets, according to a senior law enforcement official who has reviewed Homeland Security Department bulletins and warnings as well as online activity from instigators on the political right and left. But law enforcement officials fear that online posts by instigators could materialize into violent acts.
Trump supporters mounted a motorcade across the New York City region on Sunday, waving flags and cheering for the president while clogging traffic on key arteries.
The supporters were spotted crossing the Mario M Cuomo Bridge over the Hudson River in the city's northern suburbs and bringing the busy Garden State Parkway in New Jersey at least partly to a standstill.
Officials in New Jersey told a local newspaper that the motorcade stopped near the Cheesequake Service Area — about 30 miles outside New York City — and "backed traffic up for about five miles."
Supporters waved Trump flags, leaned out of their vehicles wearing "Make America Great Again" hats and honked and cheered.
The Mario M Cuomo Bridge might have been a symbolic target for Republicans — it is named for the deceased father of Governor Andrew M Cuomo, a Democrat who has quarreled frequently with President Trump.