The mother of a Swedish refugee centre worker allegedly killed by an asylum seeker at the shelter has spoken of her grief as her family blamed Swedish politicians for her death.

Chiméne Mezher described her daughter as her "angel" on Tuesday, hours after a teenage asylum seeker was charged with murder. Alexandra Mezher had been stabbed to death on Monday morning.

The young man who has not been named was taken into custody after the 22-year-old died. Swedish news agency TT said he was 15 years old.

The boy, whose country of origin was not disclosed, was interviewed, along with seven witnesses to the crime, hours after the attack.

The mother described her "fair" daughter, adding: "She was my air, she was my everything, why her?

"She was not just my daughter, she was my angel. She was a just and fair human being. There were so many who loved her. She was my daughter, my friend.. my mate," Mrs Mezher told GoteborgsPosten.

It was reported the social worker was of Lebanese Christian origin and lived 40 miles from Molndal. MailOnline reported that Ms Mezher's father moved to Sweden from Beirut in 1989, with her mother following three years later.

Ms Mezher was stabbed at the centre for refugee children aged between 14 and 17 who are without any adult guardians in Molndal near Gothenburg on Sweden's west coast.

The refugee centre employee later died of her injuries after she was taken to Sahlgrenska Hospital. The motive was not immediately clear.

The attack took place at a home for 11 unaccompanied refugee youth run by a company called Living Nordic in a converted hotel in Molndal, a suburb of Gothenburg.

Police said on Tuesday that two of the 11 residents at the home had managed to overpower the youth by the time police arrived.

"It says in the police report on the event that two guys held him down. That's an extremely good intervention," police spokesman Peter Adlersson told Expressen newspaper. "If he had been planning to injure more people, they prevented it. It's very easy to get wounded oneself if one intervenes in this way. We are extremely grateful for those who did this."

"It is obvious that the migrant situation is a great strain. It has become clear that the situation is completely unsustainable." Police union director Lena Nitz

A cousin described her as an "angel", adding: "It is so terrible. She was a person who wanted to do good, who wanted to be good.

"And then he murdered her when she was doing her job. We have cried a lot. She was such a nice person, warm and happy. It is the Swedish politicians' fault that she is dead."

Lejla Filipovic, 22, one of Ms Mezher's closest friends, told the Telegraph how much Ms Mezher loved her work.

"She was so goodhearted, she wanted to do so much in life," "She loved working with the kids, she wanted to do something good."

Ms Filipovic said that she had sometimes worried that her friend might be putting herself at risk by working with potentially traumatised refugee youth.

"I know that some of the kids aren't in a good place right now, because they came without their parents, so sometimes I was worried, but I knew that she had good coworkers."

She said that extended family from Lebanon and Israel were planning to fly to the family home in Boras, outside Gothenburg, for the funeral.

"She didn't talk so much about the work. She just said that there was a lot of work to do, never about the kids."

Police spokesman Thomas Fuxborg warned of the increase in similar incidents on Monday as the Swedish prime minister spoke of "a great worry" among people in the country.

“It was messy, of course: a crime scene with a lot of blood. The perpetrator had been overpowered by other residents," he said.

"These kinds of calls are becoming more and more common. We're dealing with more incidents like these since the arrival of so many more refugees from abroad," added Mr Fuxborg as Sweden struggles with a record influx of migrants and asylum seekers.

According to the Swedish Migration Agency, the number of threats and violent incidents at asylum facilities more than doubled from 2014 to 2015 as Sweden witnessed a record number of migrant arrivals.

In 2014, there were 148 incidents and in 2015 that number jumped to 322.

But arson attacks targeting asylum shelters have also surged, with at least two dozen centres reduced to ashes or damaged by fire last year.

Mr Lofven rushed to the asylum centre just hours after the attack, in an unusual step which underlines how much his government fears being punished by voters for its handling of last year’s refugee crisis.

“This is a tragedy. It is a terrible crime,” he said. “I think that a lot of people in Sweden feel a great worry that there might be more similar cases after Sweden took in so many unaccompanied children and youth”.

He promised Swedish police more resources to tackle the "heavier workload", dealing with border controls, security at asylum centres and the terror threat.

"The police authority have got ... a heavier workload because of the refugee situation. And then you need more resources," Swedish radio quoted Mr Lofven as saying late on Monday.

Jonas Hinnfors, politics professor at Gothenburg University, said that Mr Lofven's decision to rush to Molndal showed the difficult situation the government was facing.

"By coming here, he is showing that this is something that the government and the Social Democratic party are taking seriously," he said. "This is perhaps to dilute a little bit the criticism that the establishment have tried to cover up what people claim to be the real facts about crime and immigration."

"The dilemma is of course that, by moving onto that turf, he plays into the hands of the immigration-critical parties, because he's doing things, debating things, which normally aren't on the Social Democratic agenda."

The attack came shortly after Dan Eliasson, Sweden’s national police commissioner, handed an open letter to Sweden’s government calling for 2,500 additional police officers and 1,600 extra civilian staff to make up for those taken up by policing asylum seekers and asylum centres.

“We need to be there often, there are fights and disturbances,” Mr Eliasson told Swedish Radio of the centres. “We have placed police officers at the border controls. Unrest at the asylum accommodation centres has eaten up police resources.”

Staffan Alexandersson, the social worker employed by Living Nordic to look after the home, said that the stabbing was the first event of its kind in the more than one and a half years since it opened.

“We were surprised, absolutely shocked,” he said. “Most of the people who come to our camps are very friendly. Sometimes teenagers squabble and argue, but that’s all. We’ve never had any violence against personnel.”

A police officer is seen outside a home for juvenile asylum seekers in Molndal in south western Sweden (Photo: AFP)

Also weighing on police resources are border controls introduced on Jan 4 and a higher national terrorist threat level after the Paris attacks in November.

"Many of the problems we are now facing help to prove the point that Swedish police have long been underfunded and under-staffed," police union director Lena Nitz, told TT.

"It is obvious that the migrant situation is a great strain. It has become clear that the situation is completely unsustainable."

The police request for more resources comes as greater attention is being focused on allegations of violence by young migrants across Europe, with some countries expressing doubt about their ability to integrate them into society.

"We warned about this and now it's happened," said Tobias Hellstrom, a spokesman for the anti-immigrant Sweden Democrats party in Molndal.

"You can't leave a single girl of 22 years of age to take care of these 'youths', who often seem to be much older than they claim."

"Look anywhere in Sweden, when you collect a lot of unaccompanied minors in one place, trouble seems to happen."

Mr Hellstrom claimed that Molndal had seen a sharp rise in robberies and burglaries since unaccompanied refugee youth began to be placed in the town in large numbers a few years ago.

"Since we took in more unaccompanied minors, burglaries and robberies have gone up significantly. A lot of people get robbed nowadays," hesaid.

"What's changed now is that everybody knows it's the unaccompanied minors. The media always hid that before. They always reported that there were a lot of robberies, but they never reported who committed them."

Like the rest of Europe, Sweden has been struggling with the continent's biggest migration crisis since the Second World War.

After starting the year with Europe’s most liberal immigration and asylum regime, the country’s Social Democrat-Green coalition in November moved suddenly to tighten asylum and border rules to stem flows as high as 10,000 new arrivals a week.

The U-turn was so dramatic that Åsa Romson, the green party leader and environment minister, visibly fought back tears during the announcement.

The number of new arrivals has since dropped dramatically, to just 771 over the past week.

It has also tightened its asylum rules to curb the migrant flow.