An estimated 500 people marched Sunday through Burlington, Vermont, over government policies toward the environment, immigrants and refugees and the economy, protest organizers said.
Protesters created a "human oil spill" over the possibility that tar sands oil from western Canada might be shipped across Vermont, New Hampshire and Maine.
"It's clear the governors and premiers are meeting to talk about trade policy, energy and infrastructure," said Avery Pittman, spokeswoman for the protest groups. "They're definitely prioritizing profits and money-making over the needs of the people or the impact these proposals will have on us."
Pittman said police in riot gear fired rubber bullets on protesters, along with the pepper bullets. Police denied using rubber bullets.
Raw video posted on the website of the Burlington Free Press newspaper appeared to show an officer shooting a protester twice at close range.
Police said two officers suffered minor injuries. There were no arrests.
Protesters were fired upon, police said, "to protect officers from those in the crowd who were moving toward them."