The Highway Patrol, which provides Capitol security, locked the doors and patrolled both the building and grounds. There were no immediate reports of arrests.
"It's being done to avoid a gathering inside the building," Patrol Lt. Tom Iverson said.
More than a dozen protesters opposed to the $3.8 billion pipeline were arrested in the Capitol earlier this month when they sat, chanted and sang and refused to leave. Three others who refused to leave the nearby governor's residence also were arrested.
The rallies set for Tuesday at such places as state Army Corps offices, federal buildings and offices of banks that have helped finance the project are seeking to draw the attention of President Barack Obama.
The groups, including the Indigenous Environmental Network, Honor the Earth and Greenpeace USA, want Obama to permanently halt the construction of the pipeline, the focus of confrontations between police and protesters in North Dakota for months.
Video calling for National Day of Action at Army Corps of Engineers:
A United Nations group that represents indigenous people around the world says the U.S. government appears to be ignoring the treaty rights and human rights of American Indians opposing the pipeline.
The Nov. 4 statement from the U.N. Permanent Forum on Indigenous Issues called on the government to "protect the traditional lands and sacred sites of the Standing Rock Sioux and uphold their human rights commitments."
Forum member Edward John in late October visited a camp in North Dakota that's drawn hundreds of protesters against the 1,200-mile pipeline to carry North Dakota oil through South Dakota and Iowa to a shipping point in Illinois.
Nearly 470 protesters have been arrested supporting the Standing Rock Sioux, who believe the pipeline threatens drinking water and cultural sites. John said he found a "war zone" atmosphere and that "I felt as though I was in an armed conflict zone on foreign soil."
Justice Department officials didn't immediately comment Monday.
The federal government hasn't been silent on the dispute. The Army Corps of Engineers is reconsidering its decision to allow the pipeline to cross under the Missouri River in light of tribal complaints, and Obama has said his administration is monitoring the situation.
