The United States has placed unprecedented sanctions on an Islamic school in northwest Pakistan for allegedly training and financing fighters from al-Qaeda and other militant groups.

The sanctions against Jamia Taleem-Ul-Quran-Wal-Hadith Madrassa, also known as the Ganj Madrassa, in the city of Peshawar, were the first to target an Islamic school, the U.S. Department of Treasury said in a statement on Tuesday.

The U.S. also placed sanctions on a man accused of being al-Qaeda’s leader in the Pakistani provinces of Sindh and Baluchistan. Umar Siddique Kathio Azmarai has also been a significant financial facilitator for the group, moving hundreds of thousands of dollars to support operations, and managed logistics for Osama bin Laden’s family members, the U.S. said.

“Today’s action strikes at the heart of the financial and logistical support network that abuses charitable donations and provides essential services for various terrorist groups,” including al-Qaeda, the Taliban and Lashkar-e-Taiba, said David Cohen, undersecretary for terrorism and financial intelligence. “We will continue to work with our partners around the world to dismantle these terrorist networks, especially those that try to conceal their sinister activities behind critical community organizations like madrassas.”

The sanctions mean that any assets they may have under U.S. jurisdiction are frozen, and people in the U.S. are generally prohibited from doing business with them.

The U.S. said the Ganj Madrassa is controlled by a man known as Sheik Aminullah who was sanctioned by Washington and the United Nations in 2009 for providing material support to al-Qaeda and the Taliban.

“The Ganj Madrassa serves as a terrorist training centre where students, under the guise of religious studies, have been radicalized to conduct terrorist and insurgent activities,” the U.S said in its statement. “In some cases, students were trained to become bomb manufacturers and suicide bombers.”

In an interview with The Associated Press, one of the school’s administrators denied it had any links with militant groups.

“The institution is purely a religious school, and is not connected with any organization or involved in any sort of illegality or promotion of extremism,” said Alam Sher, who is in his eighties and helped found the school some 25 years ago.

Mr. Sher said Aminullah was a teacher at the school until he left nine months ago. School officials do not know where he is currently located, he added.

The U.S. sanctions would not affect the school because it doesn’t get any foreign aid and relies on public donations and income from his soap factory, the founder said.

The three-story school is located in a congested part of Peshawar and houses at least 150 students, mostly from poor families, said Sher. The school includes a mosque, classrooms and a hostel for the students.