OKLAHOMA CITY (AP) - Oklahoma authorities say they arrested eight people at a construction site for the Keystone XL oil pipeline, including one man who locked himself to a piece of machinery.

Seminole County Sheriff's Deputy Chris Conn says two women and six men were arrested Monday morning on trespassing complaints at the site near the town of Schoolton.

Conn says one man who locked himself to a piece of machinery was removed after a local fire department used a pair of bolt cutters to free him.

A spokesman for Calgary-based TransCanada says the incident was the second in Oklahoma in which protesters locked themselves to a piece of equipment.

A group claiming responsibility for the protest, Great Plains Tar Sands Resistance, cited environmental concerns and the oil extraction's impact on indigenous people.