Hamburg (AFP) - Some 200 Syrian and Afghan refugees clashed in a crowded German refugee centre in Hamburg overnight, leaving four people injured in the third such riot this week, police said Thursday.
Fifty police were called in to contain the mass brawl, which broke out in an argument in a shower block, local newspaper the Morgenpost reported.
The two groups attacked each other with iron bars and furniture and by hurling rocks, reported the daily and DPA news agency, citing emergency personnel in the northern port city.
The initial fight involved a 16-year-old Afghan and two Syrians aged 16 and 18, who were injured, along with a 53-year-old security guard, police said.
Police briefly detained 10 people in the initial fight, in which a garbage container was set on fire, and when tensions flared up again hours later.
Hamburg police were also called to another centre where rival groups faced off, armed with wooden poles and broomsticks, after a 19-year-old migrant accused a 23-year-old Iraqi of having stolen his mobile phone.
Police arrived with 15 patrol cars, defused the tensions and briefly detained the Iraqi and four others.
Germany is Europe's top destination for people fleeing war and misery and expects up to one million newcomers this year.
Aid workers warn that tensions easily flare as often traumatised refugees, many of them men, share crowded spaces while lacking common languages to defuse everyday conflicts.
The Hamburg centre that saw the clash between Syrians and Afghans is located in a large former hardware store and houses 800 people, with more recent arrivals sleeping on mattresses outside.
In earlier disturbances in Germany this week, 14 people were injured Sunday in a centre in the central city of Kassel when 70 Pakistanis clashed with 300 Albanians.
On Tuesday, dozens of Syrians and Pakistanis came to blows in a refugee shelter in the eastern city of Dresden.
According to southern Bavaria state, the main entry point for migrants to Germany, up to 280,000 asylum seekers arrived in Germany in September alone, topping last year's total.