HALIFAX

Mounties arrested at least 40 protesters at an anti-fracking blockade in New Brunswick after police cruisers were torched when RCMP moved in Thursday morning.

Charges include firearms offences, uttering threats, intimidation, mischief and refusing to abide by a court injunction.

Native protesters complained they were hit with rubber bullets and pepper spray. They apparently retaliated by torching at least five cop cars.

Mounties said at least one shot was fired by someone other than police and Molotov cocktails were thrown at cops.

The RCMP is also investigating other suspected explosive devices.

Mounties were trying Thursday to enforce an Oct. 3 court injunction at the standoff near Rexton, where SWN Resources Canada is testing for shale gas.

Elsipogtog Mi'kmaq First Nation members have been blocking workers' access to their trucks.

The protesters have been there since Sept. 30.

"The RCMP has worked diligently with all parties involved in hopes for a peaceful resolution. Those efforts have not been successful," RCMP Const. Jullie Rogers-Kent said in a release.

Videos posted online show some protesters cursing at cops and daring them to release their police dogs, while others yelled that there were elders and children present.

Others show a line of police stretched across Hwy. 11, moving slowly to contain the protest, and protesters washing out their eyes from what appeared to be pepper spray.

The area remained closed to traffic as police remained on the scene amid the "large gathering" of protesters, RCMP said.

AFN National Chief Shawn Atleo called for calm on both sides.

"We strongly remind the RCMP that, as in the time of treaty, their role is not to take sides in disputes, but to maintain peace," he said in a release.

The federal government had little to say about the situation, but issued a statement through the public safety office that only said it expects "local law enforcement to ensure that the law is respected."

The provincial government in the spring cautiously opened the door for shale gas exploration, while promising to defend environmental concerns. It hinted a regulatory commission could oversee development.

The protesters are concerned the process to extract natural gas by fracturing deep underground rock could damage the environment and contaminate their drinking water.

In a show of solidarity with the First Nations people in New Brunswick, protesters from Six Nations had shut down a section of Highway 6 near Caledonia, Ont.

"We've heard some things that aren't setting right and we're here to show our support to our brothers and sisters in New Brunswick," said Andrea Curley, one of many demonstrators who blocked Highway 6 at Fifth Line. The peaceful protest ended at 7:30 p.m. Thursday.

-- with files from Kris Sims and Susan Gamble