An explosive device wounded a police officer and a civilian when it detonated outside a church in central Athens early on Thursday (local time), police and state media said.
There was no claim of responsibility for the attack. The church lies in the heavily policed, upscale Kolonaki quarter which borders on Exarchia, a district where clashes between police and self-styled anarchists are common.
The blast occurred outside the Saint Dionysios church around 7am, just before it was due to open to the public for a service.
The police officer and a second person - identified by state TV as the church caretaker - were taken to hospital and police cordoned off the area.
Their injuries were not life threatening, health officials said.
"The police officer spotted a box outside the entrance of the church and thought it was strange. The blast was not powerful, the officer was injured in the face and hands," the police official, who declined to be identified, told Reuters.
Witnesses cited by state television suggested the caretaker had called police after finding the package. There was no warning call that the device would go off, the official said. Police were checking footage from surveillance cameras in the area.
Small-scale attacks on businesses, state buildings, police and politicians are not uncommon in Greece, which has a long history of political violence.
A powerful blast smashed windows and wrecked offices at Greece's SKAI TV in Athens earlier this month in what officials called an attack on democracy. No one was hurt, and no-one has claimed responsibility for that attack.
