Mail bombs exploded in the hands of employees at the Swiss and Chilean embassies in Rome, seriously injuring two people and triggering heightened security checks at diplomatic missions.

Italian investigators suspected yesterday's attacks, less than three hours apart, were the work of anarchists, similar to the two-day wave of mail bombs which targeted several embassies in Athens last month - including those of Chile and Switzerland.

One of last month's booby-trapped packages, addressed to Italian premier Silvio Berlusconi, was intercepted in Italy.

Last night Italian news agency Ansa reported that a claim by anarchists was found in a small box near one of the wounded employees and was being examined by anti-terror police.

Anti-terrorism police at Rome police headquarters refused to comment on the claim, which Ansa said was made by a group called the Informal Anarchist Federation, or FAI.

"Long live FAI, long live anarchy," the claim reportedly said.

Anarchists were blamed by authorities last week for bloody clashes between protesters and police in Rome which marred otherwise peaceful demonstrations by students against a university reform law. The legislation received final approval in parliament yesterday.

Italian investigators were pursuing the "trail of anarchists-insurrectionists", interior minister Roberto Maroni, whose ministry includes anti-terrorist police, said.

"Various elements lead us to think that this is the correct path," he said.

"These are very violent groups that are also present in Spain and Greece and are very well-connected."

In Athens, law enforcement officials said Greek anti-terror police had been contacted by Italian colleagues but that no link with the Greek parcel bombs was immediately apparent.

Rome's police chief Francesco Tagliente, rushing to the Chilean diplomatic mission, said all embassies in the city were being alerted.

For about an hour, it seemed as if the Ukrainian embassy, a few streets away from Chile's embassy, had received a package bomb. But Mr Tagliente said checks revealed the suspicious package there was a "false alarm".

Tens of thousands of tourists and pilgrims have been pouring into Rome this week for Christmas ceremonies at the Vatican. Since the September 11 terror attacks in the United States in 2001, security has been tight at public ceremonies in St Peter's Basilica and Square, with the faithful subject to metal detector checks and handbag and backpack inspections.

Swiss ambassador Bernardino Regazzoni, speaking to reporters outside his embassy, said the device which exploded had been posted, but he did not say from where.

The bomb at the Chilean embassy was sent from inside Italy, Ansa reported. But Chilean ambassador Oscar Godoy said it was not yet clear if the package - a medium-sized envelope big enough to hold documents and addressed to the cultural attache - had been posted or delivered by a messenger.

"There were no flames, just a little smoke," he said.

The bombs seemed aimed to injure if not maim or kill those opening them.

Surgeons removed an iron bolt which had embedded itself in the chest of the Chilean embassy employee who opened the package, said Massimiliano Talucci, a spokesman for Umberto I Polyclinic, where the man was admitted for treatment.

The Chilean also suffered a serious hand wound and face injuries, and risks losing the sight in one eye. The Swiss official suffered hand and chest wounds.

With Italy's mail service known for often being slow, if similar package bombs were sent by post to embassies, it might be days before they are delivered.

The package bomb addressed to Mr Berlusconi last month had been sent via a courier service on board the courier's cargo plane from Greece to Italy.

Chilean envoy Mr Godoy denounced the explosion at his mission as "an absolutely irrational and brutal act" and said there had been no threats to indicate it could be a target.

At the Swiss compound, Mr Regazzoni noted that, besides the anarchist bombs in Greece last month, in early October two bottles with a fuse were found on top of an outer wall of the embassy.

On November 2, suspected Greek anarchists sent 14 mail bombs to foreign embassies in Athens, as well as to Mr Berlusconi, French president Nicolas Sarkozy and German chancellor Angela Merkel. Two of the devices exploded, causing no injuries.

A group called Conspiracy Nuclei of Fire claimed responsibility for the Greek blasts. It called on militants in Greece and other countries to step up their action, and Greek police noted yesterday that, in the past, acts of "solidarity" have been carried out between Greek and Italian militant groups.

Foreign minister Franco Frattini said Italian diplomats abroad were urged to take precautions.

The Swiss embassy increased security after consulting Italian authorities and security at all foreign missions would be reviewed, Swiss foreign minister Micheline Calmy-Rey said. Possible extra measures, she added, could include additional protective walls or fences, surveillance cameras and evacuation plans.

There have been growing concerns in Europe about holiday season attacks following a suicide bombing in Sweden and security services' fears of an assault on a European city modelled on the deadly shooting spree in Mumbai, India.

On Tuesday there was a bomb scare in Rome's underground system after authorities discovered a suspicious package with wires and powder under a seat. The device turned out to be a fake, with police determining there was no trigger mechanism and its the powder was inert, cement-like material.

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