Concerns have been raised after it emerged that President-elect Donald Trump owns stock in a company building the hotly-disputed Dakota Access Pipeline.
Protesters – mainly Native Americans from various tribes from the area – are fighting a hard-fought battle with government representatives in North Dakota where they are campaigning against the building of a $3.7bn (£2.94bn) 1,200-mile pipeline designed to transport crude oil across four states.
As the US Army Corps of Engineers warn that they will close the land to the thousands encamped at the site on 5 December opponents of the pipeline warn that Trump's investments could affect any decision he makes on the project.
In Trump's 2016 federal disclosure forms, in which he was required to declare interests in all companies he has investments in, showed that he owned between $15,000 and $50,000 (£12,000-£40,000) in stock in Texas-based Energy Transfer Partners, which is building the pipeline.
That is down from between $500,000-$1m he held last year. In addition to this stock, Trump owns between $100,000-$250,000 in Phillips 66, which has a 25% share of Dakota Access.
Although these shares are relatively minor compared to other business interests the property mogul has, they are a potential conflict of interest. It has also been reported that at least two possible candidates for energy secretary in Trump's cabinet could also benefit financially from the pipeline.
"Trump's investments in the pipeline business threaten to undercut faith in this process – which was already frayed – by interjecting his own financial well-being into a much bigger decision," Sharon Buccino, director of environment group Natural Resources Defense Council, told the Associated Press news agency. "This should be about the interests of the many, rather than giving the appearance of looking at the interests of a few — including Trump," Buccino added.
Campaigners say the project could harm drinking water and will encroach on sites sacred to Native Americans. In past weeks, protesters have reported that they have been sprayed with water cannons and shot at with rubber bullets and tear gas.
An estimated 5,000 people are believed to be camped at the site with total arrests since August rising to 528. Trump. Through a spokeswoman, Trump said that he plans to transfer control of his company to three of his adult children.
Trump spokeswoman Hope Hicks said on Friday: "We are in the process of vetting various structures with the goal of the immediate transfer of management of the Trump Organization and its portfolio of businesses to Donald Jr, Ivanka and Eric Trump as well as a team of highly skilled executives. This is a top priority at the organisation and the structure that is ultimately selected will comply with all applicable rules and regulations."
Arizona Congressman Raul Grijalva, a Democrat who sits on the House Natural Resources Committee, called Trump's investment in the pipeline "disturbing".