Greece explosion: Bomb causes courthouse damage one day after prison bombing

A courthouse north of Athens was damaged by a bomb on Friday, the second Greece explosion in the past two days.

A powerful bomb exploded inside a courthouse in the northern Greek city of Thessaloniki Friday, sending smoke billowing in the building and wounding one person.

Police had evacuated most of the building after a Greek newspaper received an anonymous call warning that a bomb had been planted in the toilets in the building's basement.

Lawyer Babis Apostolides said one man sustained slight leg injuries, and he had transported him to a nearby hospital, where he received stitches.

Other witnesses who were still inside the building at the time said the explosion took place in the basement, and a prosecutor said she saw smoke rising to a third floor courtroom. She spoke on condition her name not be used.

Police said the blast knocked down some walls inside the building.

The bombing came less than a day after a powerful bomb exploded Thursday night outside Greece's largest prison in the Greek capital, Athens. One woman was slightly injured in that blast, cut by flying glass. That blast had also been preceded by a warning call to a newspaper.

There was no immediate claim of responsibility for the Athens attack, but suspicion fell on radical Greek militant groups that have stepped up attacks in recent years.

Last month, authorities arrested and charged six people with membership of Greece's most active militant left wing group. The Revolutionary Struggle organization fired a rocket-propelled grenade at the U.S. embassy in Athens in 2007, causing no injuries.

Several suspected members of that group are being held at Korydallos on pretrial detention.