Hundreds of migrants waiting to submit asylum applications rioted in central Athens, setting fire to rubbish bins and attacking passing cars.
Protesters said the riot began when one man fell into a nearby canal after authorities told the crowd that no more applications could be submitted. Only a small number of applications can be submitted each week.
It was not immediately clear how the man fell into the canal. Police said he was injured and was taken by ambulance to a hospital. They said they were investigating the incident.
Outraged asylum-seekers began setting fire to rubbish bins and throwing them into the street, and ripped branches off trees to set them alight. A smaller group threw rocks at passing cars, stopping some vehicles and banging on them with their hands. There were no reports of any passers-by being injured.
The riot lasted for about an hour, and riot police who were on standby nearby did not intervene. A fire truck extinguished the blazes.
In October, a human rights group said a Pakistani man was fatally injured when he fell into the same canal.
The group, Stop the War Coalition, said that the man had been trying to escape police after immigrants queuing to submit applications clashed with authorities. Police rejected claims they had any involvement in the man’s death and said they had tried to repulse an attempt by a large group of migrants to jump the queue.
Rights groups have often criticised Greece’s treatment of illegal immigrants and the living conditions in detention centres.
Greece approved only 140 of the 20,692 asylum applications made in 2007, according to the UN refugee agency. Tens of thousands of illegal migrants enter Greece each year. Many attempt dangerous sea crossings from nearby Turkey or brave minefields to make their way in.