The FBI is investigating after a "caravan" of vehicles flying Trump flags surrounded a Joe Biden campaign bus in Texas and a pick-up truck allegedly ramming a Democratic staffer's car.
Footage on social media shows pick-up trucks waving Make America Great Again signs and flags swarming the bus and accompanying vehicles on Friday.
A pick-up truck strikes a white SUV driven by a Democratic campaign staffer, Katie Naranjo. Images posted on social media show damage to the car.
After the crash, on I-35 in Hays County, Texas, Democrats cancelled three events in the state and the FBI became involved, the Texas Tribune reported.
President Donald Trump linked to a video showing his supporters surrounding the Biden tour bus, tweeting "I LOVE TEXAS" a day after the footage emerged.
During his rally in Montoursville, Pennsylvania, Trump also referred to the Texas MAGA convoy, while talking about how his supporters have been showing up to Biden's drive-in rallies.
Trump asked the crowd if they saw pictures of the Texas incident and then said "What a group" and noted that "it's like a hot thing". He added that it's "really No 1 trending".
Texas representative Rafael Anchia tweeted pictures of the Biden bus next to a hearse covered in Trump campaign flags, noting: "Armed Trump trolls harassing Biden Bus on I-35, ramming volunteer vehicles & blocking traffic for 40 mins."
Other videos and photos showed Trump supporters heckling the Biden bus - calling the Democrat's supporters communists - as it pulled out of a rest stop.
One Biden supporter tweeted about the experience.
"See all these pickup trucks with Trump flags? They were sitting along I-35, waiting to ambush the Biden/Harris campaign bus as it travelled from San Antonio to Austin," wrote historian Dr Eric Cervini in a tweet accompanying a video of a Trump convoy.
"These Trump supporters, many of whom were armed, surrounded the bus on the interstate and attempted to drive it off the road. They outnumbered police 50-1, and they ended up hitting a staffer's car."
A Biden campaign staffer told the Daily Beast that the Trump supporters seen in the highway video around the Biden bus had slowed down in front of it, attempting to either stop it or run the bus off the road.
Staffers eventually called police, who helped the Biden bus reach its destination.
Texas representative Sheryl Cole tweeted on Friday: "This is a 1st for me - but we just cancelled a joint event in Pflugerville w/@JoeBiden campaign, @AustinYoungDems, & more, due to security reasons. Unfortunately, Pro-Trump Protestors have escalated well beyond safe limits."
"Rather than engage in productive conversation about the drastically different visions that Joe Biden and Donald Trump have for our country, Trump supporters in Texas today instead decided to put our staff, surrogates, supporters, and others in harm's way," the Biden campaign's Texas communications director, Tariq Thowfeek, said.