Greece has suspended all international mail and parcel services for 48 hours after a series of mail bombs were sent to foreign embassies in Athens and other destinations in Europe.
The suspension beginning on Wednesday is being made to allow for further checks on items in transit to be carried out, a police spokesman said.
German police earlier disarmed a potentially harmful package at the German chancellor's office that arrived from Greece, just hours after similar small parcel bombs exploded outside the Russian and Swiss embassies in the Greek capital of Athens.
A spokesman for Angela Merkel, the chancellor, said the suspicious package, intercepted in the mailroom of her office, was personally addressed to the German leader and "would have been able to harm people''.
Thomas de Maiziere, the German interior minister, said that not only did the package have a Greek return address, but authorities had been able to trace that it had been sent from Greece two days ago.
"It contained an explosive device. Based on everything that we know, it was built in the same way and visually resembled the package that exploded at the Swiss embassy in Athens,'' de Maiziere said.
Late on Tuesday, a suspicious package addressed to Silvio Berlusconi, the Italian prime minister, was sequestered at Bologna airport in Italy, police said.
According to authorities the package caught fire on being opened by police at the city's airport.
Meanwhile in Greece police detonated suspect packages found at the cargo terminal of Athens' Eleftherios Venizelos, a police official said on Tuesday.
"We will detonate both packages. We cannot be sure if they contain an explosive device unless we detonate them but we believe it is the case," a senior police official who declined to be named told Reuters news agency.
Explosions in Athens
Earlier on the same day parcel bombs exploded at the Russian and Swiss embassies in Athens, while three more were detonated outside parliament, the Bulgarian embassy and a courier company.
No injuries or damage were reported following the five small explosions.
"The package went off while police were on their way, but no one was injured," said a police official describing the incident at the Russian embassy.
Vassela Cherneva, spokeswoman for the Bulgarian foreign ministry, told Al Jazeera that a controlled explosion had taken place outside her country's embassy.
"A metal detector had detected that the package had metal inside. The person whose name was on it was contacted, but they knew nothing about it so the police were called," Cherneva said.
"Authorities acted very professionally and the explosion was professional and safe for employees of the embassy and people in the street."
Another booby-trapped parcel exploded earlier on Tuesday at the Swiss embassy in Athens.
Meanwhile, Greek police said that they detonated another suspicious package in a delivery van outside the country's parliament.
Police say they suspect that far-left domestic groups are responsible for the wave of attacks that began on Monday when four mail bombs failed to reach their targets - Nicolas Sarkozy, the French president, and the embassies in Athens of Mexico, the Netherlands and Belgium.
Monday's bombs were found after one exploded at a delivery service in the centre of the capital, lightly wounding a worker at the delivery company.
Two Greek men were arrested on suspicion of plotting the attacks when they were spotted close to the scene of one of Monday's bombings.
Police said they were carrying handguns and bullets in waist pouches, and one wore body armour, a wig and a baseball cap.
One of the two was wanted in connection with an investigation into a radical anarchist group known as Sect of Revolutionaries.
Brady Kiesling, an expert on Greek far-left groups, told Al Jazeera that the explosives were all likely to have been mailed by a little anarchist group that does not aim to cause casualties.
"These are very small crude bombs, homemade, of no particular sophistication. It's an impressive stunt but it's not that dangerous," he said.
"These groups make expressions of solidarity with other anarchists around the world. The anarchists in Greece are a subculture that's been around for decades.
"[The motivation] is partly the austerity cuts, but it's more about an earlier bombing attack that led to some deaths they didn't intend.
"They went into shock for a while. Now they have come back with a new tactic aimed at publicity to put themselves on the map again".
Source: Al Jazeera and agencies