Singapore has banned two core members of the British band Massive Attack from re-entering the country following a pro-Palestinian display during a concert on July 29. The band members, identified by footage as Robert “3D” Del Naja and Grant “Daddy G” Marshall, were investigated by Singapore police for unfurling a Palestinian flag and for one member shouting “Free Palestine” on stage.

Authorities issued the individuals stern warnings and blacklisted them from returning to the city-state. Police stated that they take a serious view of acts that could potentially harm racial and religious harmony, urging foreigners to refrain from importing foreign political matters that could undermine social cohesion and the rule of law.

Massive Attack expressed surprise and disappointment with the decision in a statement on Instagram. The band noted that large portions of the audience had chanted “Free Palestine” before and after their performance. The group stated they did not anticipate that holding up the flag would violate any laws, but they were proud to have made an “impromptu expression” of solidarity with their fans in Singapore. The band urged the Singapore government to permit citizens to voice their consciences without fear of state persecution.