A view of Milan's skyline, with the Pirelli skyscraper, centre, as seen from the roof of the Lombardy Region headquarters. Picture: Luca Bruno/AP

Rome - Two separate bomb alerts went off Friday in Florence and Milan, while in a third Italian city, Livorno, police said they found makeshift explosives in a car during a routine road check.

In Milan, bomb disposal experts were called in when what looked like a grenade was spotted outside the city's court of justice, the ANSA news agency said.

It was actually a marijuana grinder, reports said.

In Florence, a suspicious pink suitcase left in Piazza Duomo, just off the city's cathedral, was blown up in a controlled explosion. The area, a tourist hotspot, was temporarily evacuated.

In Livorno, a port city 90 kilometres west of Florence, officers found four makeshift bombs that could be triggered with a remote in a shopping bag on the passenger seat of a car.

The driver was a local man with several previous run-ins with the law, but no apparent connections to terrorist organizations, the Guardia di Finanza police said in a statement.

While his motives were unclear, he was charged with illegal possession of explosives and placed under house arrest, the Guardia di Finanza added.