BISMARCK, N.D. — The head of a Texas company building the $3.8 billion Dakota Access pipeline told employees Tuesday that it is committed to the project despite strong opposition and a federal order to voluntarily halt construction near an American Indian reservation in North Dakota.

The memo to employees, which was also released to some media outlets, is the first time in months the company has provided significant details of the four-state, 1,172-mile project.

It came the same day as a planned “day of action” in cities around the U.S. and in other countries. Authorities also arrested 22 people for interfering with construction on the pipeline about 70 miles northwest of the main protest site near the Standing Rock Sioux Reservation in North Dakota.

Energy Transfer Partners CEO Kelcy Warren told employees the pipeline is nearly 60 percent complete and that “concerns about the pipeline’s impact on the local water supply are unfounded.” The Standing Rock Sioux tribe and others argue the project will impact drinking water for thousands of tribal members and millions downstream.

“I am confident that as long as the government ultimately decides the fate of the project based on science and engineering, the Dakota Access Pipeline will become operational … So we will continue to obey the rules and trust the process,” he wrote.

Standing Rock Tribal Chairman Dave Archambault II said he and the thousands of others who have gathered at an encampment in southern North Dakota to protest won’t budge.

“People are still coming down here and are committed to stopping the project,” he said.

The tribe is challenging the Army Corps of Engineers’ decision to grant about 200 permits at water crossings for pipeline, which goes through the Dakotas and Iowa to Illinois. The tribe says the project will disturb sacred sites and impact drinking water. Energy Transfer Partners disputes those claims, saying the pipeline would include safeguards and that workers monitoring the pipeline remotely could close valves within three minutes if a breach is detected.

The tribe’s effort to temporarily block construction near its reservation was denied by U.S. District Judge James Boasberg on Friday. But minutes later, federal officials ordered a temporary halt to construction on Army Corps land around and underneath Lake Oahe – one of six reservoirs on the Missouri River. Three federal agencies also asked ETP for a “voluntary pause” in work for 20 miles on either side of Lake Oahe.