ATHENS, Jan. 10 (Xinhua) -- A dozen of suspicious envelopes, at least one case of which contained a yet unknown substance, have been sent to Greek universities all over the country, local media reported on Thursday.
Five persons at the University of the Aegean on Lesvos Island were hospitalized for a few hours with minor health issues, mainly irritation in the mouth, nose and eyes and were released on Thursday afternoon, Greek national news agency AMNA reported.
In addition, four employees at the post office of Corfu Island in the Ionian Sea in western Greece were placed in quarantine as a precaution.
In all cases the recipients were the rectors of the universities and the letters were sent from India, according to information from police sources.
In some cases at the universities of Western Attica and Western Macedonia the envelopes were sent shortly before or after Christmas and after the incident on Lesvos rectors notified investigators.
So far according to the investigation, only the envelope which was opened by administrative employees at the University of the Aegean on Wednesday contained the substance, which according to experts, does not seem harmful, AMNA reported.