Greek police yesterday remained on high alert after destroying a letter bomb that had been returned to an Athens courier firm by the French Embassy. It was the 14th such device to have been dispatched, via Greek courier companies, to foreign embassies in Athens and European leaders since the beginning of the week. A spokesperson for the Greek police said the latest package was returned to the courier firm on Thursday morning after embassy staff regarded it as suspicious. The package, which bore an erroneous return address for Archbishop Ieronymos, was detonated in a controlled explosion outside the offices of the courier firm in Kallithea, south of central Athens. Police supervising the destruction of the package cordoned off the busy thoroughfare of Kallirois Street and surrounding roads for several hours, causing serious traffic problems for some time. Police also cordoned off the area around Parliament for two hours after a small package with no return address sparked an alert. The area was reopened after bomb disposal experts established that the package contained books. Counterterrorism officers inspected another three packages at a courier firm in Markopoulo, east of Athens, but the parcels were found to be innocuous. Overseas mail deliveries were expected to resume today following a 48-hour suspension after a spokeswoman for the Hellenic Civil Aviation Authority said there would be no extension. Meanwhile, the two men arrested on Monday in connection with the letter bomb plot were remanded in custody after refusing to speak to an investigating magistrate. They face charges of committing terrorist acts and membership in a terrorist organization. Panayiotis Argyrou, 22, is a suspected member of Conspiracy of the Cells of Fire, a small guerrilla group that has claimed responsibility for a string of attacks on political and business targets. Gerasimos Tsakalos, 24, is believed to be linked to a guerrilla group, though it is unclear which one. In a related development, a delegation of German police officers arrived in Athens to «exchange information» with their Greek counterparts following the discovery of one of the letter bombs in the office of German Chancellor Angela Merkel in Berlin on Tuesday.