Masked Gangs Attack Refugees in Sweden: Police

Police had beefed up their presence in the city center, deploying anti-riot and helicopter units after learning that extremists were planning "aggression on unaccompanied migrant minors" in the city late Friday, AFP reported.

"I was passing by and saw a masked group dressed in black... start hitting foreigners. I saw three people molested," the Aftonbladet daily quoted one witness as saying.

Police Spokesman Towe Hagg said by midday police had not received any complaints of assault but one 46-year-old man was arrested after striking a plain clothed officer.

Three further people were briefly detained for public order offences and one more faces charges for carrying a knife.

As many as 100 people, their faces covered, had descended in the early evening on the Sergels Torg pedestrian square, a popular meeting point for young people, including unaccompanied migrants.

Aftonbladet quoted witnesses as saying the masked group targeted "people of foreign appearance" and handed out leaflets urging the infliction of "deserved punishment on children of the North African street."

After initially taking a generous stance on migration -- the country of 9.8 million is among the European Union states with the highest proportion of refugees per capita -- Sweden has in recent days said it expects to expel tens of thousands of people over several years as it struggles to cope with the influx.

The number of new migrants entering the country has plunged since Stockholm introduced systematic photo ID checks on travelers on January 4.

The toughening of policy comes against a backdrop of rising concern over conditions in the country's overcrowded asylum facilities.