BISMARCK, N.D. (AP) - Police and activists protesting the Dakota Access oil pipeline are in a tense standoff over the activists' occupation of private land owned by the pipeline developer. Here's a guide to the latest developments and key background about the protest:
Dallas-based Energy Transfer Partners got federal permits for the $3.8 billion pipeline in July, about two years after it was announced. The project is projected to move a half-million barrels of crude oil daily from western North Dakota through South Dakota and Iowa to an existing pipeline in Patoka, Illinois, where shippers can access Midwest and Gulf Coast markets.
Supporters say the pipeline will have safeguards against leaks, and is a safer way to move oil than truck and trains, especially after a handful of fiery - and sometimes deadly - derailments of trains carrying North Dakota crude.
But the Standing Rock Sioux, other tribes and environmental groups say that the pipeline could threaten water supplies for millions, since it will cross the Missouri River, as well as harm sacred sites and artifacts. Protesters, sometimes numbering in the thousands, have gathered since April at the confluence of the Cannonball and Missouri rivers in southern North Dakota.
IN THE COURTROOM
The Standing Rock Sioux, whose reservation straddles the North Dakota-South Dakota border, are suing federal regulators for approving the oil pipeline. They have challenged the U.S. Army Corps of Engineers' decision to grant permits at more than 200 water crossings and argue that the pipeline would be placed less than a mile upstream of the reservation, potentially affecting drinking water for more than 8,000 tribal members and millions downstream.
The tribe hasn't fared well in court so far. A federal judge in September denied their request to block construction of the entire pipeline. Three federal agencies stepped in and ordered a temporary halt to construction on corps land around and underneath Lake Oahe - one of six reservoirs on the Missouri River.
The corps is reviewing its permitting of the project and has given no timetable for a decision. Meanwhile, the tribe's appeal is still pending in federal court.
Energy Transfer Partners has said construction is nearly complete elsewhere.
The tribe's fight grew into an international cause in recent months for many Native Americans and indigenous people from around the world, with some traveling thousands of miles to join the protest.
"Divergent" actress Shailene Woodley also protested and was arrested, while "Democracy Now!" host Amy Goodman had charges of rioting and trespassing charges dropped stemming from her coverage of a protest.
More than 260 people have been arrested since the larger demonstrations began in August.
As of Wednesday, nearly all of the $6 million in emergency funding earmarked for law enforcement costs related to the protest had been used up. The state's Emergency Commission approved the money in late September, and the Department of Emergency Services plans to ask for more.
Nearly half of those arrests came over the weekend, when protesters twice blocked a state highway and law enforcement said that a drone was flown dangerously close to a police helicopter.
On Sunday, a group of protesters moved onto a private property that had recently been acquired by Energy Transfer Partners, putting them squarely in the pipeline's path for the first time.
Morton County sheriff's officials called it trespassing. They said they didn't have the resources to immediately remove the demonstrators. Six states have answered the department's call for reinforcements, and Energy Transfer Partners called on the protesters to leave. On Wednesday, officers of three law enforcement agencies formally asked the protesters to go, but they said no. Police said they don't want to forcibly remove the demonstrators but will do so if necessary.
Actor Mark Ruffalo was delivering a pair of Navajo-made solar trailers Wednesday to help power the encampments established to protest the pipeline. The Rev. Jesse Jackson also visited the protests on Wednesday.
(Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)