ATHENS, Jan. 21 (Xinhua) -- Greek police detonated on Friday afternoon a suspicious package spotted at the entrance of the Regional Development and Competitiveness Ministry building in Athens, which eventually proved a false alarm.

A squad of counter-terrorism experts proceeded to a controlled explosion of the package, as Greek authorities are on alert for possible attacks by local guerilla groups.

According to early information by Greek media, experts discovered after all that the package included only a table lamp.

Greek police is on alert over the past few weeks, as local militants have threatened with attacks on "representatives of the status quo" during the trial of 13 young persons accused of terrorism activity which opened in Athens last Monday.

The youths are considered as members of the "Conspiracy of the Nuclei of Fire" group which is linked to a long series of attacks on political, police and financial targets since 2009, including the case of the more than a dozen parcel bombs addressed to foreign embassies in Athens and European leaders last November.

Last summer a stronger explosive device hidden inside a parcel addressed to Michalis Chrysohoidis, Citizens' Protection Minister at the time, killed a police officer next to his office.

Chrysohoidis currently is Regional Development and Competitiveness Minister.