UPDATED 11/2/16, 9:30 a.m. ET:

While tens of thousands of people initially checked in on Facebook at the Standing Rock Indian Reservation earlier this week in an effort to confuse police as to who is protesting the Dakota Access Pipeline, that number swelled over the last two days. According to reports, there have now been more than 1 million people who have checked in at Standing Rock and that number is reportedly growing by the hour. The Morton County Sheriff's Department continues to maintain that it is not following Facebook check-ins for Standing Rock or any other locations.

See original story below.

A group of Native protesters in North Dakota are continuing their efforts to halt plans to build an oil pipeline that would cut through the Standing Rock Indian Reservation. The protesters, who refer to themselves as water protectors, have been camped out for months while fighting against the Dakota Access Pipeline (often referred to as DAPL). The protest has caught attention around the country and around the world, and now, tens of thousands of people are using Facebook check-ins to confuse police who have violently intervened at the protest. 

Beginning Sunday, Facebook users the world over began using the check-in feature to publicly mark themselves present at the Standing Rock Indian Reservation. Soon after, these same accounts published a message explaining their check-in, but only to friends. One of the popular messages reads:

The Morton County Sheriff's Department has been using Facebook check-ins to find out who is at Standing Rock in order to target them in attempts to disrupt the prayer camps. SO Water Protectors are calling on EVERYONE to check-in at Standing Rock, ND to overwhelm and confuse them. This is concrete action that can protect people putting their bodies and well-beings on the line that we can do without leaving our homes. Will you join me in Standing Rock?

If you're sharing your location at Standing Stock:
1) Make it public.
2) Make the clarification post SEPARATE, and limit post visibility to your friends only.
3) Don't clarify on your check-in post; privately message friends who say "stay safe!" to let them know what's up.
4) Copy/paste to share clarification messages (like this one) because making it public blows our cover.
5) Use an alternate name in clarification posts so that when they filter out / search those terms, your post is visible to the right people.

Several other similar accompanying messages have been circulating Facebook as well. 

According to Snopes, the origin of the now viral post and check-in is not known. Snopes​ spoke with a representative from the Sacred Stone Camp, where protesters have been camping out to stop DAPL, who said that their camp was not the source of the check-in request. They told Snopes​: 

There is no doubt that law enforcement comb social media for incriminating material and monitor communications.

There is no solid line between "organizers" and "others," this is a movement, not an organization. There are many camps and points of contact, we can only verify that it did not originate from the Sacred Stone Camp FB page. We support the tactic, and think it is a great way to express solidarity.

Area police who spoke with Snopes denied that they are using Facebook to monitor the protest.

Supporters of the Native protesters have been using other online efforts to call attention to the protest and provide financial support. In August, a We The People petition amassed 286,167 signatures, demanding that the White House stop plans for the pipeline's construction. An ongoing GoFundMe page for Sacred Stone Camp has raised over $1,100,000 in the last six months.