Iran's foreign minister cancelled a visit with his Austrian counterpart to show displeasure that Chancellor Sebastian Kurz's government had flown the Israeli flag in Vienna in a show of solidarity, the Austrian foreign ministry said on Saturday.

Iranian Foreign Minister Mohammad Javad Zarif was supposed to meet Alexander Schallenberg but had called off the trip, a spokeswoman for Schallenberg said, confirming a report in newspaper Die Presse.

“We regret this and take note of it, but for us, it is as clear as day that when Hamas fires more than 2,000 rockets at civilian targets in Israel then we will not remain silent,” the spokeswoman said.

Hamas is the Islamist group that runs Gaza. Israel has pummelled Gaza with air strikes and Palestinian fighters have launched rocket barrages at Israel in the worst escalation of violence in years.

The dispute comes during talks in Vienna to try to revive a 2015 accord with western powers in which Iran agreed to curb its nuclear programme in exchange for relief from sanctions. Former United States President Donald Trump abandoned the deal in 2018, prompting Iran to begin violating its terms.

Kurz, who is firmly pro-Israel, had called flying the Israeli flag over the federal chancellery on Friday a mark of solidarity amid the violent clashes. But Abbas Araqchi, who heads the Iranian delegation at the Vienna talks, criticised the move.

“Vienna is the seat of (nuclear watchdog) IAEA & UN, and (Austria) so far been a great host for negotiations,” Araqchi wrote on Twitter. “Shocking & painful to see flag of the occupying regime, that brutally killed tens of innocent civilians, inc many children in just few days, over govt offices in Vienna. We stand with Palestine.”