The UN human rights chief says he’s “troubled” by heavy-handed tactics by US police during attempts to break up pro-Palestinian protests on college campuses.

“I am concerned that some of law enforcement actions across a series of universities appear disproportionate in their impacts,” Volker Turk said in a statement, in which he made reference to arrests and sanctions of students, Al Jazeera reported. 

More than 900 arrests have been made over the past two weeks across the US with video emerging of US police officers beating demonstrators with batons and firing pepper spray at students.