A noose was found in the Smithsonian National Museum of African-American History and Culture, the museum said Wednesday.
Police came to investigate and remove the noose found in the Segregation Gallery on the second floor of the museum, reopening the exhibit just three hours later, Smithsonian officials said.
This is the second noose found on Smithsonian grounds just this week.
In the United States, the noose is symbolic of lynchings of African Americans that took place primarily between the 1860s and though much of the 20th century, at the hands of white mobs.
"The noose has long represented a deplorable act of cowardice and depravity, a symbol of extreme violence for African Americans. Today's incident is a painful reminder of the challenges that African Americans continue to face," Lonnie Bunch, III, the museum's founding director, said in a statement.
"This was a horrible act, but it is a stark reminder of why our work is so important," he wrote.
Over the weekend, a noose was also found hanging on a tree outside the Hirshhorn museum of modern art, police said.
The incident was the latest in a string of public demonstrations of racism in the Washington, D.C., area.
Posters with racist messages were seen posted in a residential neighborhood in nearby Alexandria, Virginia, on Saturday. The posters have been linked to a group called "Vanguard America" that calls for America to reclaim itself as a White nation.
During the past month, similar incidents have been reported at universities and schools in surrounding areas. Bananas hanging from what appeared to be nooses were strewn across the campus of American University, just days after Taylor Dumpson was sworn-in as the school’s first female African American student government president.
Fliers with racist and white supremacist messages have been circulating at universities across the country, including Texas University and Minnesota’s St. Olaf College.
The Southern Poverty Law Center, which documents incidents of hate across the United States, recorded more than 150 reports of White nationalist fliers on college campuses in the months after the election.
It has also documented a rise in what it deems hate groups for the second consecutive year.