A group of Greenpeace activists have scaled three smokestacks at a Shell oilsands upgrader plant in northern Alberta in a call for action on climate change. Three of the protesters were arrested as they tried to gain access to the site.

According to Greenpeace, the trio are facing mischief and trespassing charges.

Mike Hudema, who works for Greenpeace in Edmonton, told the Canadian Press that more than a dozen of the protesters chained themselves to the structures, which are still under construction.

He said the group arrived at around 5 a.m. local time on Saturday morning. They wanted to send a message to officials meeting in Bangkok to discuss climate change, he said.

Many of the protesters used climbing gear to scale the giant smokestacks.

"They're all trained climbers, so they all climbed up these structures. They're locked down and they're set to stay there for a good duration," Melina Laboucan-Massimo told The Canadian Press, a few hours after the protest began.

Protesters also put up yellow banners reading "Climate S.O.S." The action was live streamed on Greenpeace's website.

Alberta Premier Ed Stelmach spoke out against the protesters Saturday, calling them "lawbreakers" and said they are "putting people on the job site at risk."

Cpl. Darren Anderson of the RCMP said the police force is in communication with the protesters and they are working towards a peaceful resolution.

A video clip posted on Greenpeace Canada's website shows a man standing in the dark in front of a large industrial facility.

"Right now we've climbed some kind of chimney that's (under) construction," the man says. "It's kind of chilly."

The activists are considering meeting with officials at Shell Canada to talk about the seizure, Hudema said.

Shell officials echoed that statement on Saturday, requesting to meet with any activists thinking of targeting its facilities.

"We reiterate our wish that Greenpeace and all other who have concerns with our activities would talk to us face to face instead of using confrontational and unsafe tactics," the company said in a statement.

"We are working with the RCMP and government authorities are being notified."

Construction is not currently underway at the site because it's the weekend, the statement continues, and production at the site has not been affected.

The protest comes days after about 20 Greenpeace activists were arrested at a Suncor oilsands plant near Fort McMurray, Alta., on Wednesday.

With files from the Canadian Press