国际英语新闻：Bomb explosion rocks main prison in Athens, one injured

The blast occurred shortly after 10:00 p.m. local time (1900 GMT) and Greek television channels interrupted their programs to report the incident. The explosion was so loud that it could be heard kilometres away in many districts of Athens.

Two years ago, a smaller bomb blast had occurred on the same spot.

According to earlier information, an unidentified man made a warning phone call to ALTER television and "Eleftherotypia" daily around half an hour before the explosion, a common practice of Greek guerrilla groups.

Police investigators search for evidence after a bomb explosion outside Korydallos prison near Athens May 13, 2010. A bomb exploded outside Athens' main prison on Thursday, causing extensive damage, but no injuries, police officials said.

Police rushed to the indicated spot and evacuated the area but did not have enough time to alert all people living in nearby block of flats.

On March 28 this year, a 15-year old Afghan boy was killed and his younger sister was severely injured in a similar bomb attack against a government building in central Athens. No warning call was made before that blast which was also attributed to " Revolutionary Struggle."

Greece has suffered from domestic terrorism for decades. The terrorist group "November 17," disbanded in 2002, was linked with a string of attacks which caused more than 20 deaths in two decades.

"Revolutionary Struggle" was the most dangerous group since then. But smaller guerrilla groups are believed to still operate in Greece which has seen a resurgence of attacks following the riots triggered by the deadly shooting of a Greek teenager by police in December 2008.

Greek police has been on alert in the past few days due to a historic visit by Turkish Prime Minister Tayyip Erdogan to Athens, which will start on Friday.