we have breaking news on the air tonight. a dramatic final showdown over the pipeline in north dakota. pictures coming in just moments ago. police moving in right there to make their arrests. abc's phillip mena is on the scene in north dakota. >> reporter: tonight, police moving in, forcibly arresting the remaining pipeline protesters in north dakota. facing a 2:00 p.m. deadline to evacuate or face arrest, some protesters began ceremonially setting fire to parts of their camp, preferring to burn it rather than have it seized and destroyed. >> that's all done with the intent of getting this area cleaned up. this area here potentially could be facing a flood soon. >> reporter: this day was inevitable. after president trump signed executive actions last month moving the pipeline plan forward. undoing a previous order from president obama, blocking it. the protesters began gathering here last april, opposing the construction of the 1,200-mile dakota access pipeline that would run from north dakota to illinois. they say the pipeline would