SUPERIOR, Wis. — Authorities have arrested six protesters at an Enbridge Energy pipeline construction site near Superior in northwestern Wisconsin.

Tuesday’s arrests were the first at the site, where Enbridge is building a replacement for its aging Line 3 crude oil pipeline from Alberta across North Dakota and Minnesota to Superior. Nobody was arrested in two protests there last week.

Enbridge says the protest interrupted construction, and it can’t continue to tolerate trespassing, vandalism or unlawful actions that put people or the environment at risk.

The six protesters face charges of trespassing and disorderly conduct. Three are from Cloquet, Minnesota; the others are from Michigan, South Dakota, and Saskatchewan.

Environmental and tribal groups oppose the project. Honor the Earth says more protests are planned this weekend at Enbridge sites in Wisconsin and Michigan.