Opinion polls show most Swedes support immigration and that many are more tolerant of foreigners than 20 years ago.

But while those opposed to immigration are in a minority, their number may be on the rise and could be further boosted by the riots.

“It will be a step to increasing polarization on the issue of integration in Sweden,” said Andreas Johansson Heino, a political scientist at Sweden’s Timbro think-tank. “These kinds of things benefit parties like the Sweden Democrats.”

Some 43,900 asylum seekers arrived in 2012, a nearly 50 percent jump from 2011 and the second highest on record. Nearly half were from Syria, Afghanistan and Somalia and will get at least temporary residency. There was a total of 103,000 new immigrants.

Some 15 percent of Sweden’s population is foreign born, the highest in the Nordic region. Asylum seekers in particular are drawn by Sweden’s robust economy and tradition of helping refugees.