The mayor of Florence has apologised after yelling “Allahu Akbar” as a joke at his Venetian counterpart after a debate which discussed radicalisation and terrorism.

The two mayors were at a conference in Rimini, on Italy’s Adriatic coast, when the bizarre encounter happened.

They had just left a debate in which Luigi Brugnaro, the mayor of Venice, said that if any terrorist was thinking of attacking his city, he would be gunned down by the security forces within seconds.

“If someone shouts Allahu Akbar while running through St Mark's Square, we'll shoot them,” Mr Brugnaro said. “A year ago, I said (they’d be shot) after four steps, now I’m saying it would happen after three.”

To hammer home the point, he also issued the warning in Venetian dialect, telling his audience “Ghe sparemo” – “We’ll shoot them”. After the debate was over, Mr Nardella burst into a room yelling “Allahu Akbar”, to the amusement of Venice’s mayor and other delegates.