The heavy police presence outside Cologne's Gothic cathedral is not enough to make 16-year-old Lisa Elsner feel safe going out in a city-centre still reeling from mass assaults on women on New Year's Eve.

"Not alone, and certainly not at night," she said, her father nodding in agreement beside her.

They are sitting at a cafe just outside the main train station, which lies in the shadow of the twin-spired cathedral and was the scene of much of last week's violence, in which 121 women are reported to have been robbed, threatened or sexually molested by gangs of men, many of them foreigners.

The area is a bustling hub not only for many of Cologne's 1.2 million people but also for the tourists seeking out its historic sights, and the thousands of revellers due in town for days of raucous Rhineland carnival - now just four weeks away.

Yesterday, the city's police chief was relieved of his duties after criticism that the force had been too slow to deal with the attackers.

But as well as raising questions about policing, the attacks have triggered a furious debate about Chancellor Angela Merkel's immigration policy, which saw 1.1 million asylum seekers come to Germany last year, the bulk of them from Syria, Iraq or Afghanistan.

The German Interior Ministry said yesterday that, out of 32 suspects identified so far, 27 were from North Africa or the Middle East, and 22 were seeking asylum.

‘It's just too much’

Shawn Barsohn, 17, said he blamed Merkel for the incident.

"She let in too many and now she has to see that it is just too much," he said, as a large Christmas tree was dismantled on the square in front of the station.

Barsohn's friend Maryam Dweiri, 13, agreed: "She is not in control of the refugee crisis ... When I walk here at night, I feel anxious."

Their concerns are shared by many of the refugees who have recently come to Germany.

Syrian Kurdish cousins Kasedli and Majed Hassan, who arrived four months ago and live in a shelter for asylum seekers an hour's drive from Cologne, fear that the attacks will erode German compassion for the refugees.

"Germany welcomed us here like no other country. Not even Arab countries want us," said Majed, 27.

Kasedli added: "For those guys to do what they did is shameful. Even if they had been sober, they should not have behaved like this. It is totally barbaric."

The cousins decided to visit Cologne after reading about the attacks in Arab media; the subject now commands their attention more than the war back home.

Huda, an Iraqi mother who made it to Germany two months ago and was seeking directions to a Turkish women's clothing store with her teenage daughter, was more blunt: "They are abusing the freedom they have here in Germany. They are bastards, not Muslims."

But Reinhard Zoellner, mayor of the poor district of Chorweiler, where high-rise blocks built in the 1960s are home to migrants from 120 countries, said he had noticed no outward tension in his area since the attacks.

Like many German cities, Cologne has a significant Turkish population dating back to an influx of 'guest workers' in the 1960s and 70s.

Multi-cultural city

"We are very multi-cultural, we are very tolerant," he said. "Such events won't change that."

He said the key to preventing such attacks in the future was integration of the immigrants.

At the modest Abu Bakr mosque, in a working class neighbourhood some 3 km north of the cathedral, young Arab men, mainly from North Africa, spoke of their fear that Germans will put the attacks down to general disrespect for women among Muslim and Arab men.

"I understand why they think that. I am German, I was born here," said Yakup, a bearded 22-year-old computer science student at the University of Cologne, who declined to give his family name.

"My religion teaches me to think with my heart. So my advice is: 'Let's not blame the whole group for the actions of a few'."

Sitting in his office before yesterday's sermon, imam Moutawalli Moussa was still angry about the incident.

"I condemn it in the strongest terms," he said. "Islam forbids men from setting their gaze on women, especially if they are not covered."

But he also said police had been too slow to react - and that Merkel was partly to blame for the situation.

"They took in more than they can handle," he said. "Where will they house all the people?"

- Reuters

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