D.C.'s mayor has enacted an emergency regulation to block a possible plan by the federal government to put a shelter for unaccompanied migrant children in the nation's capital.

The emergency rule from Mayor Muriel Bowser became effective immediately on Friday and restricts the size of shelters for unaccompanied children at 15 occupants.

"This emergency action is necessary to immediately protect the health, safety, and welfare of children receiving care in a youth shelter, emergency care facility, or youth group home, by ensuring these children have the adequate supervision and care necessary for their well-being," the legislation states.

The rule will expire on Dec. 14.

The Washington Post reported on Aug. 13 that federal contractor Dynamic Service Solutions applied to open a temporary shelter, and local lawmakers are under the impression that it could be built on private property in Takoma, which is in Ward 4, near the Maryland border.

Dynamic Service Solutions has posted on job boards seeking bilingual youth care workers, medical staff case managers and a lead teacher who would work with UAC, or unaccompanied "alien children."

Bowser said the city will not accept such a shelter.

"Washington, D.C., will not be complicit in the inhumane practice of detaining migrant children in warehouses," Bowser said in an emailed statement.

Bowser said the city had already closed "a shelter that was too big to succeed because we know that such impersonal spaces are not what our most vulnerable families and children need."

The DC General shelter, which housed hundreds of homeless families at points, was shut down in October. It had become notorious for mold, rats, overcrowding and the disappearance of 8-year-old Relisha Rudd, who was not reported missing until several days after she vanished with a shelter employee.

"We have no intention of accepting a new federal facility, least of all one that detains and dehumanizes migrant children," Bowser said.

Ward 4 Council Member Brandon Todd, who represents the Takoma neighborhood, said he was shocked and appalled at the proposed site, which could house more than 200 children.

"I refuse to stand idly by while the Trump administration recklessly puts children in danger leaving irreparable, lasting trauma," he said in a statement on Twitter.

"I do not care if it's 100 children or 1 child," he said. "I will do everything in my power to fight against this inhumanity."

Earlier this month, it was revealed that the federal government was also eyeing Northern Virginia for a facility that could hold migrant children.

More than 69,000 unaccompanied children were apprehended at the border between October and July, The Associated Press reports. The Trump administration has been scouting sites for more shelters in response to the influx of children who arrived in the U.S. alone or were separated from their caregivers at the border.

Some detention centers have been criticized for subpar sanitation and care.

The Washington Post reports that the facility is still in the application phase and must be approved by the D.C. Child and Family Services Agency and the D.C. Department of Consumer and Regulatory Affairs.