Anti-Israel protesters burned diplomas outside Columba University Wednesday demanding the release of Mahmoud Khalil who was arrested by immigration agents in March.

NEW YORK–Columbia University’s acting president defended higher education and acknowledged the absence of Mahmoud Khalil during the school’s commencement ceremony, as pro-Palestinian demonstrators protested outside the school’s main gates.

Last year's graduation ceremony was called off due to safety concerns after an anti-Israel protest encampment took over the campus for several weeks during the spring.