Police on the Greek island of Lesbos on Monday fired tear gas at hundreds of migrants protesting against tougher new asylum rules, officials said.
Brandishing makeshift signs with the word "freedom", some 2,000 men and women walked out of the overpopulated camp of Moria to demonstrate.
The protesters walked some seven kilometres (4.3 miles) towards the port capital of Mytilene, but were blocked by police outside the town.
"A significant backlog of pending applications and serious delays in asylum procedures have been a major contributing factor to the dangerously overcrowded conditions we see on the islands," Boris Cheshirkov, Greece spokesperson for the UN refugee agency, said in a statement to AFP.
"Long waiting times are also contributing to the mental toll that people are facing," he said.
After years of procedural delays, Greece faces a backlog of almost 90,000 asylum applications, Cheshirkov said.
In 2019, Greece became the first port of entry for migrants and refugees entering Europe.
The government has struggled to manage the influx, keeping many in overcrowded camps on the Aegean Greek islands near the Turkish coast.
More than 40,000 asylum-seekers are currently crammed into camps on five islands, where the official capacity is for 6,200 people and in conditions repeatedly condemned by aid agencies.
The conservative government of Prime Minister Kyriakos Mitsotakis has toughened its approach to asylum-seekers and is trying to speed up the repatriation of people whose applications have been rejected.
At Moria, where over 19,000 people live in and outside a camp built for fewer than 3,000, many are housed in tents and makeshift shelters without access to power, heating, or hot water, Cheshirkov said.
"There aren't enough latrines and showers and access to health is severely limited," he said. There are also frequent outbreaks of violence.
- 'Dissuasive message' -
The new Greek minister for migration Notis Mitarachi, appointed just two weeks ago, has vowed to expel "on a weekly basis" migrants whose asylum applications are rejected.
"Those not entitled to international protection will be rapidly returned to Turkey," Mitarachi told Kathimerini daily on Sunday.
"We believe... this will send a loud and dissuasive message to human smugglers," he said.
In another apparent attempt at deterrence, Greece's defence ministry last week put out a call for a floating barrier in the Aegean to stop migrant boats.
The system -- criticised as unethical and impractical by opposition parties -- could involve either barriers or nets, 2.7 kilometres (1.7 miles) long, and would be used as an emergency measure by the Greek armed forces.
Police clashed with migrants protesting against tougher new asylum laws
The conservative government of Prime Minister Kyriakos Mitsotakis has toughened its approach to asylum-seekers