Italian police have defused a suspect package addressed to the Spanish airline Iberia at Rome's Fiumicino international airport.

Police explosives experts were called in after the package raised the suspicions of staff at the airport's post office.

This is the latest in a series of explosives devices aimed at Spanish targets, after two parcel bombs were sent last week to the airline at Milan's Malpensa airport and at its offices in Rome.

Suspect packages

16 Dec: Package sent to Iberia's Rome airport office 14 Dec: Letter bomb sent to Iberia's Milan airport office 13 Dec: Package sent to Iberia's Rome headquarters 12 Dec: Spanish newspaper El Pais in Barcelona sent parcel from Milan

In a possibly related development, Spanish police said on Thursday they had defused another bomb sent by mail from Milan, received at the Barcelona office of the Spanish newspaper El Pais.

Italian police have warned employees of Spanish companies in the country to be on the lookout for more suspicious packages.

On Saturday, Italian police defused a bomb, consisting of powder in an envelope with a timing device attached, sent to Iberia's offices at Milan's Malpensa airport.

On Friday, a bomb was found hidden in a book left at Iberia's Italian headquarters in Rome. The device was destroyed in a controlled explosion.

Authorities said on Monday that all four bombs had been sent from Milan and that the package discovered on Monday was very similar to the others.

A leaflet similar to those contained in the other packages was found in the latest bomb, the Italian news agency Ansa reports.

Unknown group

Spain's Interior Minister, Angel Acebes, said on Thursday that the package sent to El Pais was claimed by an unknown group, the Five Cs, opposed to capitalism, prisons and prison officers.

News reports said that the same group signed the leaflet found with the letter-bomb at Milan airport on Saturday.

The leaflet reportedly contained threats to Valentino Rossi, the reigning world MotoGP champion who was given police protection over the weekend.

News reports said on Sunday that Mr Rossi was targeted because of a team sponsor, Spanish energy group Repsol-YPF which was among the Spanish targets cited by the group.

It was unclear whether a suspect package, which was sent by post to Italy's state broadcaster RAI early on Monday, was linked to the devices sent to Iberia.

The package, which reports say contained a book, burst into flames, but no-one was injured, the network said.