olice found guns and ammunition after searching an apartment and car in Exarchia, central Athens, on Tuesday night.
Officers said they discovered two Kalashnikov assault rifles, four stun grenades and hundreds of bullets.
Earlier, police searched an apartment in Piraeus. It is thought the properties are linked to the two armed bank robberies carried out in Velvento, northern Greece, last month as well as possible terrorist activity.
Four men declaring themselves to be anarchists have been arrested for the robberies. Another four suspects are being sought.