A Melbourne firefighter says the carnage that has unfolded in Barcelona reminds him of the Bourke Street rampage, in which he was a first responder.
More than 16 people were killed and more than 100 injured when a white van ploughed into crowds in Barcelona; the attack has been claimed by Islamic State.
"I heard a large rumbling sound to begin with, a shot.. and some time after that screams and the horrific scene down there," said MFB Commander Graeme O'Sullivan, who witnessed the attack.
He is on holiday with his wife and was at his hotel near Las Ramblas, a shopping and tourist district similar to Bourke St, when the attack happened.
O'Sullivan described hearing rumbling, followed by shots which he identified as a hand gun – believed to be the sound of the attackers firing into the crowd.
He said the scene reminded him of Melbourne's January 20 Bourke Street Mall, when a man in a car mowed down pedestrians, killing six people.
"It's very similar [to Bourke Street]," AAP reported.
"Bourke Street wasn't terrorism and this appears to be, but the result is still the same."