French President Nicolas Sarkozy was among the intended recipients of four parcel bombs found in Athens on Monday, Greek police have said.
One of the bombs, addressed to the Mexican embassy in Athens, exploded in the offices of a private courier company, slightly injuring an employee.
The other two parcels were addressed to the Belgian and Dutch embassies in the city.
Two men, aged 22 and 24, have been arrested over the attack.
Greece has been experiencing a wave of attacks against government and police targets, attributed to far-left groups, and police said they were not linking Monday's events to al-Qaeda.
Wigs and guns
The first package detonated when a woman working at the courier company became suspicious of the contents and threw it to the ground.
Another package addressed to the Dutch embassy was found at the offices of a second company and a controlled explosion was later carried out.
As police arrived, two men described as wearing wigs and bulletproof vests and carrying handguns, were arrested at a bus stop.
At this point, two further packages were found, addressed to the French president and the Belgian embassy.
One of the men detained is suspected of being a member of an anarchist group, Conspiracy of Fire, thought to be behind a string of crude bomb and arson attacks.
Left-wing groups were blamed for a parcel bomb explosion in June in which a close aide to Greece's counter-terrorism minister was killed.