Unidentified law enforcement agents detained a parent outside Talbot Community School after they dropped their child off at the school in Portland on Thursday, the district’s superintendent said in a letter to the school community.

Superintendent Ryan Scallon said that the agents wore vests marked “police,” but were in unmarked vehicles and refused to identify themselves. The parent was detained around 8 a.m. Thursday on the school’s access road, he said.

“A district administrator approached the officers to inquire about their presence. The officers did not state what agency they represented,” Scallon wrote in his letter. He didn’t identify the parent.

The district confirmed with the Portland Police Department that none of its officers were involved, Scallon said. He also noted the department has said “that if they learn of any proposed enforcement action planned at a school, they will work to ensure that it does not occur there.”

Brad Nadeau, a spokesperson for the police department, confirmed that the department was not involved and said it was unaware of the situation when it took place. Nadeau did not answer a question about whether the department is working to determine what occurred.

“While we do not have confirmation which organization these agents represented, members of our community are concerned about Immigration and Customs Enforcement’s (ICE) presence in our city,” Scallon wrote. “Our school leaders have been provided instructions on what to do should an immigration enforcement agency or other unknown individual approach staff or students or try to enter a school.”

A spokesperson for ICE did not reply Thursday night to phone and email inquiries.

The superintendent described the incident as “troubling” and the impact on the school community as “chilling.”

Scallon emphasized the school’s policy entering this school year, which is to “cultivate safe and inclusive school communities,” and provided a link to the district’s protocols when dealing with non-local law enforcement, which can be found on the district’s website.

Scallon did not immediately respond to an inquiry for more information on Thursday night.

This is a developing story.