SANDUSKY, Iowa (AP) — At least 15 people were arrested Saturday during a protest intended to block the construction of a major oil pipeline through southeast Iowa.

More than 150 protesters gathered at the work site entrance of the $3.8 billion Dakota Access Pipeline in Sandusky, a Mississippi River town across the river from Illinois and five miles north of Missouri.

Protesters were arrested after walking through a line of private security and Lee County sheriff's deputies who were standing in front of the driveway to the work site, according to the Burlington Hawk Eye newspaper.

Last month, 30 protesters were arrested at different pipeline construction site in Iowa on trespassing charges. All but one of them took responsibility for the action and were ordered to pay just over $270 in fines and fees. One pleaded not guilty and faces a trial.