KUALA LUMPUR, Malaysia (AP) — Singapore has banned the two core members of British band Massive Attack from reentering the country after they displayed a Palestinian flag and expressed support for the Palestinian cause during their concert in the city-state last week.

Singapore police said in a recent statement that the two men were investigated over their actions during the July 29 concert, including the unfurling of a foreign flag and one member shouting “Free Palestine” on stage.

They were issued stern warnings and blacklisted from returning to the city-state, it said.

“The police take a serious view of acts which could potentially harm the racial and religious harmony in Singapore and urge the public, including foreigners, to refrain from importing foreign politics as this can undermine our social cohesion and the rule of law,” it said.

The police did not identify the men involved, but footage shared on local media showed it to be Robert “3D” Del Naja and Grant “Daddy G” Marshall.

Massive Attack responded in a statement on Instagram, saying the band was “surprised and disappointed” by the decision.

The group said large sections of the auditorium had chanted “Free Palestine” before the start of their show and at the end of it. The group said they didn't expect that merely holding up the flag would violate any law, but that they were proud to have made the “impromptu expression” with their fans in Singapore to show solidarity for the Palestinian cause.

They urged the Singapore government to allow their citizens “the expressions of conscience without fear of state persecution.”