Nearly 500 racially motivated attacks have been carried out over the past six months in Greece according to the Migrant Workers Association, as immigrants say that the rising wave of xenophobic violence has left them afraid to walk the streets.

The victims were in most cases attacked with steel rods, knives and brass knuckles, the association says.

A 19-year-old Iraqi was attacked outside a makeshift mosque in central Athens on Sunday morning by five individuals on motorcycles and struck multiple times with what appears to have been a knife, police said. The victim was taken to hospital but died several hours later.

The government condemned the killing which took place against the backdrop of an unprecedented crackdown on clandestine immigrants in the greater Athens area. Police said on Monday that the operation, code-named Xenios Zeus, has so far led to the arrest of 1,596 unregistered immigrants.

A total of 7,361 foreigners have so far been rounded up for checks, police said.

Operation Xenios Zeus has been criticized by a number of non-governmental organizations including the Greek Council of Refugees, Amnesty International and Human Rights Watch.

Greece's main left-wing SYRIZA opposition party as well as KKE Communists have also slammed the crackdown.

“We are afraid to walk around. It's Ramadan [the Islamic month of fasting], we're invited for dinner and we don't go. If we go outside, we will be caught either by the police or by Golden Dawn,” an immigrant, who did not identify himself, told Kathimerini in reference to Greece's neofascist party whose members have been linked to similar attacks in the past.