Columbia University mathematics professor Michael Thaddeus has condemned US citizen Mahmoud Khalil’s arrest, saying it has “dealt a severe blow to that trust placed in us by the world”, Al Jazeera reports.

Khalil, a student, was arrested and attempted to be deported over his participation in protests against Israel’s war on Gaza at Columbia University in New York.

“My activist colleagues behind me on the faculty have for many years circulated petitions and signed open letters in support of political prisoners held by authoritarian regimes in places like Russia, China and Iran,” Thaddeus said.

“Now we’re facing a horrifying reality that our own student, a member of the Columbia community, has become a political prisoner here in the United States. This is a dismal moment in American history,” he was quoted as saying.