Greek far-right group Golden Dawn has blamed the country's government after two of its members were shot dead, saying it had asked for police protection at its offices after receiving threats.
"(Prime Minister Antonis) Samaras's anti-Greek government is to blame for the crime, which allowed out-of-control terrorists to murder young kids in cold blood," the party said in a statement.
No one has claimed responsibility for the attack, although a police official told Reuters the force suspected unnamed anti-establishment groups.
Greek far-right group Golden Dawn said on its website that two of its members, aged 20 and 23 years old, were killed in today's shooting in Athens.
However, police have not yet verified the identities of the victims.
The Greek authorities said the gunmen who shot dead two members of the far-right Golden Dawn group today will be "dealt with unsparingly".
Government spokesman Simos Kedikoglou told reporters:
The murderers - whoever they are - will be dealt with unsparingly by our democracy. Let everyone know this.
Police sources have said at least two people were killed in a drive-by shooting outside the offices of Greece's far-right Golden Dawn party in Athens.
A member of the Greek far-right group Golden Dawn has been killed in a drive-by shooting, ITV News sources have said.
Two other Golden Dawn members were reportedly critically injured in the attack, which took place outside the organisation's offices in Heraklion, Athens.
Bulgarian authorities say a DNA test has confirmed that a Bulgarian Roma woman is the mother of the Greek mystery girl.
The girl has been in the care of a Greek charity after she was seized from the home of another Roma family.
A Bulgarian Roma woman, Sasha Ruseva, has denied taking money for giving up her baby to another Roma family years ago, as she faces preliminary charges of selling the child known as Maria to a Greek couple.
Ms Ruseva, who has eight chiildren, said she gave birth to a girl while working as an olive picker in Greece “several years ago”, but said she was forced to leave the child behind because she could not afford to take her home.
She told Bulgarian TV: “I intended to go back and take my child home, but meanwhile I gave birth to two more kids so I was not able to go back.”
Bulgarian Roma woman Sasha Ruseva, who faces preliminary charges of selling the Greek child Maria, has been pictured with her fair-skinned, blonde-haired son Atanas.
Maria was taken away from a Greek couple after authorities suspected that she was unrelated, due to her blonde hair and fair skin which did not match the couple's dark hair and tanned skin. DNA tests have since confirmed that the child is unrelated to them.
Ms Ruseva has a second fair-skinned child, who has striking red locks. Ms Ruseva said she wanted Maria back if DNA tests prove she is her daughter.
A Roma woman in Bulgaria has undergone DNA testing to determine whether she is the mother of the mystery blonde girl Maria, who was taken from a couple in Greece after she was suspected to be unrelated to them.
The 35-year-old Blugarian, Sasha Ruseva, is now under investigation after she said she once left a baby behind in Greece. She faces preliminary charges of child-selling.
DNA tests show that the blonde-haired, pale-skinned child called Maria is not related to the Greek couple with whom she was found.
Three people have been arrested on suspicion of abducting a two-month-old baby in Greece, police have said.
A police official said the suspects tried to get a birth certificate with only a signed statement, as is possible in Greece, instead of producing hospital records, which aroused suspicion.
Regional police chief Panagiotis Kordonouris told The Associated Press that a 19-year-old woman, her 21-year-old male companion and his mother were arrested at a Roma settlement on the island of Lesvos.