Athens, Greece (CNN) -- An explosion occurred Friday in a court building in the Greek city of Thessaloniki, police said.
A warning was issued to local media before the explosion and the building was evacuated in time.
No injuries were reported.
The blast happened at 1:30 p.m. local time (6:30 a.m. ET) Friday.
It follows an explosion on Thursday night near a prison in Athens, Greece, police said. That blast caused slight injuries to a 22-year-old woman, police said.
The bomb on Thursday night was placed outside the Zalaxias supermarket about 660 feet (200 meters) from the Korydallos prison, authorities said.
Warning calls had been made around 9:50 p.m. -- 27 minutes before the explosion -- to the Eleftherotypia daily newspaper and Alter television station, police said, and authorities evacuated the area.