Athens: Three unknown assailants gunned down a reporter in Athens Monday, the first murder of a journalist in Greece in more than 20 years, police have said.

Greek political parties and journalist unions expressed outrage at the killing of 37-year-old Sokratis Giolias outside his home in the Athens suburb of Ilioupoli.

"Somebody wanted to silence a very good investigative reporter who had stepped on a lot of toes with his stories," said Panos Sobolos, president of the Athens journalists' union. Giolias was assassinated on his doorstep, succumbing to multiple wounds from a pistol fired at close range, police said.

Giolias, news chief at radio station Thema 98.9 and father of one child, died instantly. Police were investigating possible motives.

His murder was the first killing of a journalist in Greece since the mid-1980s, when left-wing urban guerrilla group November 17 assassinated a conservative newspaper publisher.

However, Greek newspapers and television stations have been subject to several violent attacks.

Last year, an extremist group opened fire on the headquarters of private Greek television station Alter, without causing any injury.