Rome explosion: Italian police respond to blast outside post office

Police suspect anarchist groups of responsibility following similar attacks

Forensics officers at the site of an explosion outside a post office in Via Marmorata, Rome, on 12 May (AFP/Getty Images)

An explosion has rocked a post office in Rome in what police believe is a "demonstrative act".

No injuries were immediately reported after the blast, which damaged a nearby car and sparked panic among workers at the Poste Italiane office.

Investigators believe it may have been caused a device set off by a timer, Il Giornale reported, but the target was unclear.

The homemade device was placed between cars parked in Via Marmorata, which links the River Tiber with the Pyramid of Caius Cestius in central Rome.

Massimo Improta, a police official, said the bomb was constructed using two bottles of flammable liquid inside a plastic container

Police told reporters there was no immediate suspicion of Islamist terrorism, with officers believing the blast was a "demonstrative act, showing that it could be done"..

Suspicion turned to anarchist groups, which have carried out similar firebombings in the past.

The perpetrators were suspected of links to an arson attack in a warehouse on the southern outskirts of Rome.

The post office, an imposing Fascist-era building that is often studied by architecture students, remained opened throughout the incident.

Italy's postal service has previously been targeted by anarchists because it owns Mistral Air, which flies migrants to controversial identification and expulsion centres.

A similar explosive device that did not detonate was found outside a post office in Turin in November.

Security in the Italian capital has been heightened following a series of Isis-linked terror attacks across Europe, with the terrorist group singling out Rome as a symbolic target in its propaganda.

Letter bombs have also been found in Paris, Germany and Greece after being sent by a Greek anarchist group to EU ministers and financial institutions.