A small blast outside Pizzeria Sorbillo in the city's historic center early Wednesday damaged the eatery's metal grating.
The ANSA news agency said eight bombs have targeted Naples-area businesses in recent days. Last month, a pizzeria was bombed in the nearby town of Afragola. The attacks are under investigation.
Chamber of Deputy President Roberto Fico, a Neapolitan, decried "vile" intimidation attacks by the Camorra, the Naples-area crime syndicate.
Gino Sorbillo's pizzeria, which was torched five years ago, draws lines of residents and tourists.
Extortion is a Camorra mainstay. Businesses refusing to pay "protection" money risk attacks. Italy's interior minister said there's state funding to hire 100 more Naples police officers.
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