A North Dakota government official has condemned Barack Obama for his response to the Dakota Access pipeline protests, accusing the president of allowing Native American activists to “keep escalating their violent activities”.

As a tense standoff between protesters and police continued on Wednesday afternoon, Cody Schulz, chairman of the Morton County commission, slammed Obama for saying he was monitoring the situation and was “going to let it play out for several more weeks and determine whether or not this can be resolved in a way that I think is properly attentive to the traditions of the first Americans”.

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Schulz, a leading elected official in the region where the anti-pipeline demonstration has emerged, said in a statement Wednesday afternoon: “When President Obama says he wants to let the situation ‘play out for several more weeks’, it affords the opportunity to the out-of-state militant faction of this protest to keep escalating their violent activities.”

He continued: “Rather than creating further uncertainty, the president should be sending us the support and resources necessary to enforce the law and protect people’s right to peacefully protest. Given the recent escalation of violence by protesters, letting the situation ‘play out’ is quite literally putting lives in danger.”

The comment signals how aggressively police are responding to the Standing Rock Sioux tribe and thousands of their supporters who have set up camps for months to try and stop construction of a $3.7bn oil pipeline that they say is destroying sacred lands and threatens their water supply.

Given the recent escalation of violence by protesters, letting the situation ‘play out’ is ... putting lives in danger Cody Schulz

The US army corps of engineers has temporarily delayed permits to allow Energy Transfer Partners, the pipeline operator, to dig on federal land near or under the Missouri river. Activists have since criticized Obama for staying silent as construction has moved very close to the banks of the river and the protest camps, and some were disappointed by remarks in an interview with news site NowThis.

On Tuesday night, the president said: “We’re monitoring this closely and I think as a general rule, my view is that there is a way for us to accommodate sacred lands of Native Americans, and I think that right now the army corps is examining whether there are ways to reroute this pipeline.”

Some Native American protest leaders said they were skeptical that the federal government could find a way to change course at the last hour. They said they were were also upset that Obama did not condemn the police for conducting mass arrests and using pepper spray, bean bags and army tanks in a highly militarized response to unarmed demonstrators.

The remarks from Schulz, who did not immediately respond to a request for an interview, also reveal growing tensions between the federal government and North Dakota, which has brought in police officers from around the country to assist.

Despite the army corps’ request that the pipeline “voluntarily pause all construction activity” within 20 miles of the federally controlled water, the company has continued rapid construction in North Dakota. At the same time, local police have set up strictly enforced road blockades to protect the sites from protesters and the general public.

Arlana Curley, a Cheyenne River Sioux tribe member who has been at the protest camps for months, said people were devastated that Obama hadn’t made a stronger statement in support of Native Americans.

“Everybody’s hurt. Everybody’s upset,” she told the Guardian on Wednesday. “I felt it was very arrogant for him to say that he would wait it out and monitor. Why are they sitting there monitoring this when they are seeing all these state officials breaking the law?”

She added, “A lot of people are really hurt that the president isn’t helping us. Nobody is stepping in.”

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