Immigration advocates rallied on the steps of the New York City Department of Education's headquarters on Thursday morning, demanding a student's immediate release from federal custody. 

Mamadou Mouctar Diallo's teachers joined city leaders at the rally and said he should be in his classroom at Brooklyn Frontiers High School, instead of a U.S. Immigration and Customs Enforcement detention center. 

Diallo, a 20-year-old asylum seeker from Guinea, was detained by ICE agents last week following a routine immigration court appearance at 26 Federal Plaza in Lower Manhattan, advocates said.

The Department of Homeland Security said in a statement Diallo, "crossed the Southern border illegally as part of a caravan of 51 other illegal aliens apprehended by CBP on Jan. 13, 2024," adding "Diallo was released into our country by the Biden administration. ICE arrested him on Aug. 4, 2025. He will remain in ICE custody pending removal proceedings."

ICE confirmed he is being held at a correctional facility in Pennsylvania. 

"Take a good look at this young man who came here from his home in West Africa. He's alone," City Councilmember Rita Joseph said while holding his picture at the rally. "Mamadou did the right thing. He showed up for his routine check in and he was abducted. A student seeking a better life, pursuing his education, has been stripped." 

Diallo's teachers at Brooklyn Frontiers said he was focused on his studies, making friends and contributing to his community. The school's website says it is a transfer school "serving students who are over-age and under-credited."   

"He's a very bright, sweet, respectful young man that was going to a court date that was unjustly taken," one of Diallo's teachers said. 

"For me, to be standing here today to advocate for one of my students to be released from ICE, it's just horrible," Pedro Grand said. 

"He recently completed a culinary internship. He's completed a security guard training program and is excited to get to work. He's a member of the Audubon Society," City Councilman Lincoln Restler said. "He's a model student."  

At least 3 NYC public school students detained by ICE

Diallo is at least the third New York City public schools student detained by ICE this year, according to city immigration advocates. A 20-year-old named Dylan was detained in May and also has not been released. A 19-year-old named Derlis was released in July after spending a month in custody. 

Mayor Eric Adams' office said the administration is reviewing potential legal actions it could take in Diallo's case. 

"We are aware that one of our students has been detained by ICE after attending a routine immigration hearing. We are gathering more information and reviewing next steps, including our legal options. This did not occur in a school, and we urge our families to continue to send students to school, where they are safe," a City Hall spokesperson said. 

City Schools Chancellor Melissa Aviles-Ramos previously issued the statement, "Our team is standing with the student's family, working closely to connect them with legal support and other critical services."

New York is a sanctuary city and ICE agents are not permitted on public school grounds without a court order, subpoena or warrant signed by a judge.

School starts in New York City on Sept. 4.