Police in Athens said on Wednesday that three suspects arrested on Monday while robbing a supermarket in the central neighborhood of Ambelokipi were believed to have carried out a total of 11 such raids at supermarkets in the capital.
The suspects are two Greeks aged 33 and 42, and a 42-year-old Palestinian.
They were found in possession of two replica firearms and 5,432 euros in cash.
The men have been arrested in the past on suspicion of carrying out robberies.
They are thought to have started targeting supermarkets in May.
Meanwhile, a supermarket in Exarchia, downtown Athens, was raided late on Tuesday night.
Two men held up the store using guns.
It was not clear how much money they escaped with.