Pro-Palestinian demonstrators lit flares and chanted anti-Israeli slogans outside the Sydney Opera House to protest a decision to illuminate the iconic building’s sails in the colors of the Jewish state’s flag.

More than 1,000 people gathered outside the Opera House for the rally on Monday evening, police said, with Australian Broadcasting Corp. reporting protesters chanted “free Palestine” and “shame Israel.” At least one flare was thrown at the building after it was lit up in the blue-and-white of Israel’s flag.

New South Wales Police Assistant Commissioner Tony Cooke said Jewish Australians were discouraged from approaching the Opera House on Monday night due to concerns for their safety. Charges may be laid against people who attended the pro-Palestine rally if they committed offenses, he added.

“This is very clearly an emotive issue,” Cooke said at a press conference in Sydney on Tuesday morning. “We do not expect people to bring conflict from other places to the streets of Sydney, and violence will not be tolerated.”

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Prime Minister Anthony Albanese and New South Wales Premier Chris Minns condemned the protest, with Minns describing it as “abhorrent.” Australia has supported Israel’s right to defend itself in the wake of the weekend attacks by Hamas militants.