A culture of rape and sexual abuse is being allowed to take hold in asylum centres across Germany as Europe struggles to cope with the migrant crisis, it has been alleged,

Women’s rights groups and politicians have highlighted assaults against women and children in at least one camp.

And they suggest such incidents may be widespread, with many going unreported to the police.

Campaigners also claimed some men saw unaccompanied women as ‘fair game’, and also blamed conditions in which occupants were unsegregated by gender or nationality.

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Allegations: A culture of rape and sexual abuse is being allowed to take hold in asylum centres across Germany as Europe struggles to cope with the migrant crisis

Around 5,000 asylum seekers have been crammed into old US military bases in Giessen, western Germany

The warnings came after German Chancellor Angela Merkel earlier this month announced there was ‘no limit’ to the numbers of migrants her country would take.

Germany is expected to receive up to one million migrants this year and has since imposed temporary border controls.

But some cities have been struggling to cope with the influx, reporting intolerable pressures on housing and too few staff to process asylum claims.

And other EU countries have accused Germany of encouraging the crisis – then trying to resettle migrants in other EU countries under a quota system.

Makeshift centres in Germany have seen men, women and children having to sleep next to each other in tents, halls and corridors. Showers and toilets are often not separated by gender, and some do not even have a curtain for privacy.

In the case highlighted yesterday, around 5,000 asylum seekers have been crammed into old US military bases in Giessen, western Germany. A letter addressed to the Minister of Integration and Social Affairs in the state of Hesse, where the centre is based, from four women’s organisations described a ‘culture of rape and violence’.

The letter, written on August 18, stated: ‘It is a fact that women and children are unprotected. This situation is opportune to those men who already regard women as their inferior and treat unaccompanied women as “fair game”. As a consequence, there are reports of numerous rapes, sexual assaults and increasingly of forced prostitution. These are not isolated incidents.’

There are fears the number of unreported cases of rape and sexual assault at the Geissen camp is significant

Laundry hung out to dry on a fence surrounding former US army housing barracks used as a refugee centre

Women were often too afraid to walk around the camp even during the day, volunteers claimed, while some victims are too terrified to report sexual assaults by the men.

A police spokesman said there were ‘probably’ many unreported sexual abuses. Giessen City Councillor Astrid Eibelshaeuser said: ‘We know there is rape happening.’

Johannes-Wilhelm Roerig, the federal commissioner for child sexual abuse issues, said: ‘I am most concerned that refugee children in camps, gymnasiums, or former barracks are not sufficiently protected from sexual assault.’

Campaign group Women For Refugee Women said the solution was to integrate genuine refugees as quickly as possible into society to remove them from the risks of overcrowded conditions. Its director Natasha Walter said: ‘People should not be in detention centres, they should be in the community where they can avail themselves of the normal protections given to citizens by the authorities.’

Hungary has started to roll out barbed wire along its border with Slovenia to keep refugees out.

This is the first such known measure to take place between countries belonging to the Schengen zone.

It has already set up barriers along its frontiers with Serbia and Croatia.