The Latest on disputes over the construction of the Dakota Access oil pipeline in North Dakota (all times local):

8:30 a.m.

The number of arrests related to protests over construction of the Dakota Access oil pipeline in North Dakota has surpassed 600.

The Morton County Sheriff's Office says 16 people were arrested Monday and Tuesday in confrontations with police near the protesters' main encampment near the Standing Rock Sioux Reservation. That pushed the number of arrests since August to 603.

The tribe and its supporters say the $3.8 billion pipeline to carry North Dakota oil to a shipping point in Illinois threatens drinking water and cultural sites. Pipeline developer Energy Transfer Partners disputes that.

The pipeline is nearly complete except for a stretch beneath a Missouri River reservoir that's the tribe's water source. Whether ETP has permission to lay pipe under Lake Oahe is tied up in the courts.


7:50 a.m.

The Army says it's planning to study the potential environmental impact of routing the $3.8 billion Dakota Access pipeline under the Missouri River in North Dakota, although a judge could stall the study.

The Army published a notice in the Federal Register Wednesday of its intent to prepare an environmental impact statement on the Lake Oahe crossing.

The Army won't allow developer Energy Transfer Partners to resume the pipeline's construction while the study is ongoing. A study could take up to two years.

ETP has asked U.S. District Judge James Boasberg (BOHZ'-burg) to block the study until he rules on whether ETP already has the necessary permission for construction from the Army Corps of Engineers. The Corps says it doesn't.

Boasberg will consider ETP's request during a Wednesday afternoon hearing.