BURLINGTON, Vt. (AP) — As American and Canadian officials begin discussing issues their regions have in common, protesters will be making their concerns known from the streets.

Protesters are expected back today for the second day of the 36th annual meeting of the New England governors and eastern Canadian premiers in Burlington.

On Sunday, as regional leaders began arriving for the conference, protesters took part in events dubbed “Convergence on the Conference.”

An estimated 500 to 600 people attended a rally at City Hall before marching through downtown to protest government policies toward the environment, immigrants and refugees, and the economy, protest organizers said.

Protesters created a “human oil spill” at Burlington’s Battery Park to decry the possibility that tar sands oil from western Canada might be shipped across Vermont, New Hampshire and Maine. Members of the Occupy movement also held a regional gathering at the park in the afternoon and evening.

Police said two officers suffered minor injuries during a skirmish with protesters blocking buses that were attempting to take conference participants to dinner. They said 8-10 pepper balls and a “stingball round” containing rubber pellets were fired and that pepper spray was used.

There were no arrests and no other reports of injuries.

Avery Pittman of Burlington, spokeswoman for participating protest groups, said while protesters speak out on a variety of issues ranging from power transmission lines and oil pipelines to Vermont Yankee nuclear power plant, the governors and premiers and their staffs will be meeting “behind closed doors” today to discuss issues that have wideranging impacts.

“It’s clear the governors and premiers are meeting to talk about trade policy, energy and infrastructure,” Pittman said. “They’re definitely prioritizing profits and money-making over the needs of the people or the impact these proposals will have on us, the people who live on the land and are affected by the decisions.”

Pittman said on Sunday police in riot gear fired rubber bullets on protesters, along with the pepper bullets. Police denied using rubber bullets, only the stingball pellets.

Raw video posted the website of the Burlington Free Press appears to show an officer shooting a protester twice at close range.

In a three-page statement, police said a small group of protesters “chose to actively inhibit” the movement of 200 people headed to a dinner event.

Numerous warnings were issued, police said, and by about 5 p.m. some protesters began blocking the buses by locking arms, sitting or lying on the ground.

Police said a protester dragged an officer 20-30 feet while he was trying to make arrests and that a second officer fell over a sign on the ground, losing his helmet.

Protesters were fired upon, police said, “to protect officers from those in the crowd who were moving toward them.”