Police swarmed the corner of 6th Avenue and West 48th Street in the heart of Midtown, where a cage appeared on the street corner Wednesday morning.
The cage, which was chained to a street sign, appeared right in front of the Fox News Studios and contained what appeared to be a small mannequin with the sign "#NoKidsInCages."
Nearly a dozen NYPD officers responded to the scene. The chain was cut and police covered the cage as they continue to work to find out who placed it there.
That was not the only location where the mysterious installations popped up — around two dozen cages containing the realistic-looking child-sized mannequins were placed throughout the city, the Associated Press reported.
The mannequins depict crying children wrapped in blankets, and speakers in at least some of the cages play audio of real children crying for their parents after being detained by border officials.
Social media users have been posting photos of the cages they have encountered across New York City — including one in front of the New York Times building and another on 18th Street near Gramercy Park — using #NoKidsInCages.
At least one witness also reported seeing one of the cages installed near Columbia University.
The #NoKidsInCages campaign, intended to draw attention to the detention of migrant children at the southern U.S. border, was launched by the Texas-based Refugee and Immigrant Center for Education and Legal Services (RAICES Texas) along with the NoKidsInCages movement.
The movement advocates for the immediate end to the separation of children from their families at the border and aims to reunite the separated families, according to the NoKidsInCages website.
"This is not history. This is happening now. Hundreds more have been separated. 6 children have died," the website's message reads. "#NoKidsInCages is about the children. We cannot be a nation that separates families."