During the Glastonbury performance, which is aired annually on BBC, one of the group’s members, Bobby Vylan, led the crowd to chant, “Death to the IDF,” referring to the Israel Defense Forces, to the shock of organizers and onlookers.

Bob Vylan, known for mixing grime and punk rock, tackle a range of issues including racism, homophobia and the class divide in their songs and have previously voiced support for Palestinians.

The Glastonbury Festival is making headlines for controversy rather than music. Little-known rap-punk duo Bob Vylan have drawn politicians’ ire and a police probe after leading a chant calling for “death” to the Israeli military.