Arson attacks have increased sharply since police killed a teenager last year
Greek police have said they suspect anarchists were responsible for a number of firebomb attacks in the capital, Athens, on Thursday.
Home-made devices went off outside the home of top anti-terrorism prosecutor Dimitris Papangelopoulos, the offices of a judge and a communist newspaper.
One person was hurt in the incidents. No group has claimed responsibility.
Officials have been targeted repeatedly since police shot dead a teenager in December, triggering a month of riots.
Last week a previously unknown group, the Sect of Revolutionaries, said its members had opened fire at a police station in an Athens suburb.
In January, a policeman was shot and seriously wounded in central Athens. The attack was claimed by another better-known group, Revolutionary Struggle.
Police said the explosive devices made of gas canisters, which were used in the six attacks on Thursday, were favoured by anarchists.
An elderly lady was slightly injured in one incident when she jumped from a balcony in fright after a device exploded outside the office of the daughter of a former Greek foreign minister, Theodoros Pangalos.