Montgomery Blair High School students protest the election of Donald Trump, marching in Wheaton and Silver Spring Monday. (Toni L. Sandys/The Washington Post)

Montgomery County police are investigating complaints involving the driver of a pickup truck who allegedly displayed a handgun Monday to a group of students who were part of an anti-Trump march in the streets of Silver Spring.

Three people have reported the incident to police, said Officer Rick Goodale of the Montgomery County Police Department. Before police received the complaints, the driver came forward to report the encounter to police, Goodale said.

Police are investigating whether the man had a proper permit for the handgun and whether he threatened the students with the gun in any way.

Police have received dozens of tweets about the confrontation, including one that contained a photo of the man in the cab of his truck holding the gun in his right hand with the barrel pointed down, Goodale said.

The incident came during Monday’s protest, which included hundreds of students from Montgomery Blair High School who left classes and took to the streets, joined by students from two other high schools.

Students in the Washington region and across the country say that because they were too young to vote, their voices were not heard in the Nov. 8 election. The Maryland marchers said they were opposed to Trump and his divisive remarks about immigrants, Muslims, women and others. “Not our president,” students chanted.

One Blair student, Aran Mazariegos, 16, said the confrontation with the driver occurred shortly after 10:40 a.m. near a McDonald’s entrance.

He said the man was coming from the McDonald’s parking lot and revved his engine as he approached the teenager in the road. The teenager ran out of the way but said the driver pulled across the street, where he blocked one group of students from walking forward and leaned out his window to exchange words with another group. Cellphone video captured the truck entering the roadway and driving through the line of protesters to cross the road.

A few students tapped on the backside of the man’s truck at one point when the truck stopped, but then students rushed away, saying the man had a gun.

“I was pretty scared, not just for myself, but for other people,” Mazariegos said.

That day, he said, friends mentioned that the driver’s truck had a Trump campaign sticker, a detail he later noticed in the video that surfaced. Many other drivers, he said, had honked their horns in support of the protesters.

The student’s mother, Janet Mazariegos, reported the encounter to police.

“These are tense times, and I think violence on either side needs to be reported and dealt with,” Mazariegos said. “I was proud of these kids for demonstrating peacefully, and then to have an adult behave in this manner and brandish a gun was just reprehensible.”