Developers of a $3.8 billion, four-state oil pipeline halted construction Tuesday while law enforcement and tribal leaders in North Dakota met to discuss a resolution to a protest of the project.

Morton County Sheriff Kyle Kirchmeier says he met with tribal leaders to “negotiate peace” to ensure the safety of everyone involved.

Dakota Access filed a lawsuit in federal court on Monday against protesters. Dakota Access’ complaint alleges protesters are putting the safety of workers and law enforcement at risk.

The sheriff says 28 protesters have been arrested since last week for interfering with the construction of the Dakota Access pipeline that’s designed to carry North Dakota crude to Illinois.

Kirchmeier says the peace talks will be ongoing. He says construction is slated to resume Wednesday.