A cargo jet carrying a suspicious envelope made an emergency landing in Bologna late Tuesday evening after Greek authorities received information that the package -- reportedly destined for the office of Italian Prime Minister Silvio Berlusconi -- contained explosives.

The incident came after roughly 13 parcel and mail bombs were intercepted and neutralised in the greater Athens area on Monday and Tuesday, most addressed to foreign embassies in Athens and one headed to French President Nicolas Sarkozy's office.

Two arrests were made on Monday along a busy Athens street of suspects believed to have mailed one such mail bomb minutes earlier. According to police, the two suspects -- both local men in their early 20s -- were armed and found in possession of similar parcel bombs.

Initial reports claim the pair is linked to the ultra-leftist, self-styled anarchist terrorist (ANA-MPA) underworld active in the Greek capital in recent years, with a law enforcement investigation now in high gear, as another five suspects are wanted. The incidents are unrelated to the recent mailings of more powerful parcel bombs from the Middle East to US destinations, cases believed to be the work of Islamic terrorists.

The emergency landing came hours after a bomb disposal squad conducted a controlled detonation of two envelopes discovered in the cargo terminal of Athens' Eleftherios Venizelos International Airport on Tuesday evening.

According to initial reports, the envelopes were first isolated, with one was destined for Europol headquarters at The Hague and the other for the European Court of Justice.

The private cargo plane took off from Athens carrying the letter addressed to Berlusconi's office and was first headed to Paris before its final destination of Lyon, where the plane's load of cargo would have been sorted and forwarded to recipients.