ROME (AP) -- A man smashed a sculpture by Chinese artist and activist Ai Weiwei during the private opening of his exhibition in the northern Italian city of Bologna, in an act of vandalism that the show's curator described Tuesday as a "reckless and senseless act."

The large blue and white "Porcelain Cube" was part of the exhibition "Who am I?" inaugurated at Bologna's Palazzo Fava on Saturday.

Italian media reported that local police arrested a 57-year-old Czech man, who said he was an artist. He was known for targeting important works of art in the past.

It is still unclear how the man gained access to Friday's invitation-only event, but the museum confirmed that the exhibition opened to the public as planned on Saturday.

According to the artist's wishes, the work's fragments were covered with a cloth and removed. They will be replaced by a life-sized print and a label explaining what happened.

Ai shared CCTV footage of the attack on his Instagram account, which showed the man hanging around the work before moving suddenly behind it and pushing it so that it smashed on the gallery floor.

The man then held a broken fragment in a gesture of triumph, before the museum's security blocked him, pulling him onto the floor.

"The act of vandalism against Ai Weiwei's work 'Porcelain Cube' is even more shocking when we consider that several of the works on display explore the theme of destruction itself," said the exhibition's curator Arturo Galansino.

"The destruction that Ai Weiwei depicts in his works is a warning against the violence and injustice perpetrated by those in power, and has nothing to do with this violent, potentially dangerous, reckless and senseless act," he added.

Galansino described the attacker as "an habitual troublemaker seeking attention by damaging artists, works, monuments and institutions."