ATHENS, GREECE - A top Greek judge's car was destroyed in a bomb blast while a tax office caught fire in a separate attack and another bombing targeted a government-affiliated migration organisation, police said.

The car of the chairman of the Council of States, Greece's top administrative court, was gutted in the explosion of a gas canister bomb that was planted under his service car. Nobody was injured in the attack.

Judge Panagiotis Pikrammenos had just been appointed the previous day in a scheduled justice ministry handover.

The anti-terrorist service launched a probe into the tax office bombing in the central district of Ambelokipi, believed to be the work of Revolutionary Struggle, a far-left group that fired a rocket at the US Embassy two years ago.

Half an hour before the blast, which caused a fire that was put out before it could spread, anonymous warnings were telephoned to two Greek dailies, the police said.

Revolutionary Struggle, which features on the European Union's list of terrorist groups, more recently launched two strikes against US-based banking group Citibank and attacks on police that nearly killed a young officer.

In another attack, a gas canister bomb exploded outside the offices of the government-funded Hellenic Migration Policy Institute (IMEPO), causing minor material damage and no injuries.

Frequent bomb attacks in Athens and the northern city of Thessaloniki are often reported to be the work of extreme leftist groups or the anarchist movement.

Extremist hits against police and business targets intensified after police fatally shot a teenager in December, unleashing a wave of youth protests and violence which emboldened radical groups according to analysts. --AFP