Four protesters were arrested Tuesday morning after occupying the downtown Vancouver office of Imperial Metals, the company responsible for the Mount Polley tailings pond disaster.

Police said a group of protesters gathered outside the Hornby Street office shortly after 9 a.m., and some of them forced their way inside.

“Police received reports that three of four of the more aggressive individuals began to yell and shout as well as shove and push staff,” Const. Brian Montague said in an email statement.

Officers were called to the building and arrested four people, who remain in custody as investigators gather witness statements and review video footage of the incident.

Protester Sacheen Seitcham of the Secwepemc Women’s Warrior Society had a different account of what happened, insisting the group’s intention was to hold a peaceful protest and speak with company president Brian Kynoch.

Seitcham said the situation only grew heated after staff members became aggressive with protesters.

The purpose of the gathering was to mark the recent two-year anniversary of the Mount Polley spill, which was one of the worst mining accidents in Canadian history, and to speak out against other Imperial Metals projects in B.C.

“The mining disaster pumped billions of gallons of toxic tailings into salmon spawning headwaters. We’re here to protect the salmon, the future for our children,” Seitcham told CTV News outside the company’s office.

“We want them to get out of our territories, to cease and desist all operations as soon as possible.”

After the arrests, police said the remaining protesters continued to demonstrate outside the Imperial Metals office “in a loud, but lawful” manner.

The Secwepemc Women’s Warrior Society also blockaded an Imperial Metals mine near Likely, B.C. last week, a protest against the provincial government’s recent decision to grant the company a permit to resume full operations at Mount Polley.

Protesters said two years after the spill, little remediation has been done to clean up the site.

Imperial Metals has assured its storage facility at Mount Polley, which was found to have been inadequately designed, has been repaired and improved, and that the company is working to do better with its business.

With files from The Canadian Press