The two bombs that exploded at the Swiss and Russian embassies in Athens and the several other suspicious packages, are the work of an extreme left-wing group, according to terrorism experts.

The believe the "bomb" wave against Embassies in the Greek capital is a coordinated campaign of the group called the Conspiracy of the Cells of Fire, which is trying to spark revolution in Greece during times of austerity measures and country-wide discontent.

First reports said the device at the Swiss embassy had been thrown into a courtyard by an employee, but police later informed it had been left at the entrance and when the external packaging was removed, its contents burst into flames.

A suspected bomb was destroyed at the Bulgarian embassy, where the building was sealed off as experts carried out a controlled explosion on a suspicious parcel.

Another suspected device addressed to the Chilean Embassy was handed to the police from the driver of a delivery van outside the Greek Parliament and destroyed. The Chilean Ambassador later announced the package was addressed to her personally, adding two people have been arrested in this case. A search of a second package mailed to the Chilean Embassy failed to discover any traces of explosives.

Greek officials said another was intercepted at the offices of a courier company addressed to the German embassy.

BBC further reports that parliament security also investigated a suspicious package sent to the political office of former premier Costas Simitis, which contained a replica of an explosive device but finally proved harmless.

According to Greek press, another "suspicious" parcel, addressed to the German embassy, was intercepted by police before reaching its destination, while yet another parcel was intercepted later at Akti Miaouli in Piraeus, reportedly destined for the embassy of Panama and is expected to be neutralised through controlled explosion.

No injuries have been reported.

The string of attacks began Monday when a bomb, addressed to the Mexican Embassy in Athens exploded at a delivery truck, leaving a worker hospitalized with burns.

Police later arrested two suspects and found three more bombs, one addressed to French President Nicolas Sarkozy; the others to the Belgian and the Dutch Embassies.

The parcel bombs have raised anxiety levels in Greece in the run up to this weekend's vital local elections, the BBC correspondent in Athens says.

The elections are seen as a referendum on the socialist government's handling of the economic crisis and Prime Minister George Papandreou has warned he may call a general election if his party is soundly defeated.