Athens:
A powerful bomb exploded in front of an institute for training public officials in the west of
Athens, killing a 15-year-old boy and injuring a girl and her mother, police said.
The boy was killed on the spot while his 10-year-old sister was seriously wounded and their mother escaped with slight injuries in the blast that occurred shortly before midnight on Sunday.
Police said the family, Afghan nationals, were probably walking past the building when the explosion took place.
The girl was rushed to a nearby hospital in critical condition after the bomb placed in a bag went off without warning in the city's busy Patissia district at 10:50 pm (local time).
Greek anti-terrorism police cordoned off the area.
Attacks on public buildings and businesses are relatively frequent in Athens and the northern city of Salonika, but rarely injure anyone as there are usually warning calls that allow police to clear the area.
The last attack to have injured anyone was in October 2009, when six police officers were wounded in a machine gun attack on a police station.
Greece has been rocked by a string of attacks against economic interests and offices of politicians since a youth was killed by a police officer in December 2008.