Unidentified attackers opened fire on the German ambassador's residence in Athens with an assault rifle early today.

Police said no one was hurt in the attack, which happened at 3.40am local time (1.40am Irish time).

At least four shots hit the metal gate of the high-security residence, which lies on a busy street of a northern suburb.

Sixty spent bullet cases have been collected from the scene.

Anti-German sentiment has grown during Greece's prolonged economic crisis.

Many of those struggling with record unemployment and plummeting living standards blame Germany's insistence on fiscal rigour for their economic woes.

Germany is the biggest single contributing nation to Greece's €240bn bailouts, which have kept the country afloat since 2010 and saved it from bankruptcy.

The German ambassador's residence was the target of an attack in 1999, when members of the now dismantled extremist group November 17 fired a rocket-propelled grenade that hit its roof.

Greek Prime Minister Antonis Samaras spoke to German ambassador Wolfgang Dold, who was at home at the time of the incident.

Foreign Minister Evangelos Venizelos expressed his "outrage and outright condemnation" over the attack.

It was a "cowardly terrorist act clearly targeting Greece's image abroad a few days before the start of the Greek presidency," Mr Venizelos said, according to a statement from the Foreign Ministry.

Greece takes on the rotating European Union presidency for six months starting 1 January, hoping to show how far it has come since it almost crashed out of the common currency bloc 18 months ago.

No one has claimed responsibility yet for the incident.

A police official, who spoke on condition of anonymity, said at least two assailants on foot were involved.