The phrase means "God is great" and is frequently used in Muslim daily life
The mayor of Venice has warned that anyone who shouts "Allahu Akhbar" in the city's main square will be shot.
Controversial right-wing politician Luigi Brugnaro made the threat following the Catalonia terror attacks.
“In contrast with Barcelona, where they had not set up protection, we keep our guard up,” he said.
“If anyone runs into St Mark’s Square shouting ‘Allahu Akhbar,’ we will take him down.
"A year ago I said after four steps, now after three."
Switching to the Venetian dialect he continued, "Ghe Sparemo" - which translates as "we will shoot him."
His comments come amid heightened security concerns ahead of the annual Venice Film Festival.
The phrase "Allahu Akhbar" meaning "God is great" is frequently used in Muslim daily life - including during the call to prayer which takes place five times a day.
Italy is home to approximately 2.2 million Muslims.
It is not the first time the Mr Brugnaro has courted controversy. In 2015 he pledged to ban gay pride parades from Venice, calling them "buffoonery, the height of kitsch.”
"There will never be a Gay Pride in my city," he told the la Repubblica newspaper. "Let them go and do it in Milan, or in front of their own homes," he said.
He also became involved in a public spat with British singer Elton John after he banned books featuring same-sex couples from the city's schools.
Mr Brugnaro's "Allahu Akhbar" threat was not taken too seriously by other delegates at the conference - with the mayor of Florence, Dario Nardella jokingly shouting the phrase at him later on the day.
Mr Nardella later apologised online to anyone who felt the joke trivialised terrorism or mocked Islam.