BENNINGTON, Vt. — Protesters disrupted an event Sunday evening where people gathered to paint a Black Lives Matter mural, and blocked efforts to finish it on Monday.

Tensions ran high at the festival-style gathering in Bennington, Vt., which was designed to be family-friendly, with live music and free snacks during the painting work. At one point, a crowd of painters joined hands around the mural to block protesters who did not agree with its message.

Police estimated that 125 to 150 people attended in total; about two-thirds attended to support the mural, while a third came to protest.

Police arrested four people, including self-proclaimed white nationalist Max Misch, on charges of disorderly conduct — tampering with painted portions of the mural, or for pushing and shoving. Police did not arrest people for protesting the mural or occupying the space.

Sunday’s event was scheduled to end at 7 p.m., and organizers said that, because paint was spilled during an argument, they didn’t have enough paint to finish the mural. Coordinators planned to finish it this morning, but protesters again occupied the mural — including one carrying a rifle, said Bennington Police Chief Paul Doucette.

The mural, designed by local artists, reads “Black Lives Matter,” with the “I” shaped like the Bennington monument. The letters sit on top of the Green Mountains. Artist Cynthia Taylor said she and the two other artists, Beth Newman and MaryJane Sarvis, had consulted with people of color within the community about the project.

“We were inspired by the Hollywood sign, but we gave it a specific Bennington touch by adding the monument where the ‘I’ is,” Newman said.

Bennington Selectboard members approved the mural in late July, but some protesters wanted the decision brought to a town-wide vote.

“The request that came to us, we just felt it was really consistent with Bennington values, and felt it was important to pass it right away,” said sSelectboard Chairman Donald Campbell. “It’s a representative government.”

Mary Gerisch, a Bennington resident and co-chair of the statewide advocacy group Rights and Democracy, said she arrived Sunday at 1 p.m. to find several protesters occupying the space in front of the town offices, where she and artists would soon outline the mural.

The team began drawing the letters in chalk at 3 p.m. Gerisch said she had a polite encounter with a protester who moved so that she could continue drawing.

“At first I thought, everyone’s going to be reasonable about this,” she said.

By 4:30 p.m., a group of several anti-BLM protesters had gathered in front of the police department, across the street from the mural, and several protesters sat on the mural’s first several letters, blocking painters from the “B” and “L” in “Black.” A group of people from both sides of the conflict surrounded them, and police darted in and out of the crowd when conflict arose.

“We tried to intervene, and we tried not to make arrests, but then it got to the point where it was time,” said Doucette, the police chief.

When a woman poured the contents of her water bottle onto the mural, police handcuffed her and walked her into the police department, prompting applause from some of the crowd.

“She took the water and sprayed it at people,” Doucette said. “That’s threatening behavior. We don’t know what’s in that water bottle, and paint’s expensive.”

Misch engaged in a verbal altercation with a painter that caused paint to spill, Doucette said. Misch then walked through the mural with wet paint on his shoes. His arrest also produced cheers.

“That’s disorderly behavior. That’s tumultuous behavior. You’re ruining a mural that people worked hard to paint,” Doucette said.

Bennington police made two other arrests, Doucette said, for pushing and shoving. He added that, based on comments on social media leading up to the event, he expected it would be contentious. Eleven officers were on hand.

While police allowed acts of civil disobedience, such as blocking the painters’ work, they did not allow protesters to deface the mural. The department and the town set up video cameras that will monitor the mural around the clock.