Police were investigating a hand grenade attack on a precinct in Kaisariani which occurred in the early hours of Monday but which the authorities only discovered later after the perpetrators posted a message on an anarchist website.
The grenade was lobbed into front of the precinct to express solidarity with Constantinos Giagtzoglou, the jailed terrorist suspect who is on hunger strike, demanding his transfer back to Attica's high-security Korydallos Prison from a Larissa penitentiary. He was moved to the Larissa prison on Saturday.
Giagtzoglou, 29, is believed to have sent the parcel bomb that seriously injured former prime minister Lucas Papademos in May 2016 and wounded an employee of the International Monetary Fund office in Paris in March of that same year.
On Sunday, unidentified assailants scattered flyers outside Papademos's home in Palaio Psychico, and spray-painted slogans on the sidewalk in solidarity with Giagtzoglou.
The hand grenade detonated some 20 meters away from the police precinct at 6 a.m., near a grocery, it later emerged, smashing the shop's windows and causing damage to parked cars.
A taxi driver who had been parked close by was injured in the legs by shrapnel during the blast which he initially thought had been due to one of his car lights exploding. He had been looking for something in the trunk of the vehicle when the explosion occured.
In a message posted online, the unidentified perpetrators said a claim of responsibility would be made public soon.