The bombs had barely exploded in Stockholm's bustling shopping district before members of the far-right, Islam-bashing Sweden Democrats rushed to their blogs and Twitter feeds. "Told you so," said one. "Finally" tweeted another.
The government and just about every editorial page has warned against blaming Sweden's growing Muslim minority for the Dec. 11 suicide attack carried out by an Iraqi-born Swede, who appears to have been radicalized in Britain.
But the far-right fringe is doing just that in another challenge to Sweden's famed tolerance, already frayed in recent months by the Sweden Democrats' entry into Parliament and a serial gunman's sniper attacks against people with dark skin.
Authorities say there's a risk that even more extreme groups, long marginalized in Sweden, will use the opportunity to advance their positions.
"The biggest worry isn't that the Muslim community will become radicalized but what this means for the view of Muslims in Sweden," said Erik Akerlund, police chief in Rinkeby, an immigrant suburb of Stockholm nicknamed "Little Mogadishu" because of its large Somali community.
While investigating the attack, the Swedish security service is also keeping an eye on any potential reaction from right-wing extremists, said Anders Thornberg, the agency's director of operations. Those groups have kept a low profile since a series of attacks on immigrants and left-wing activists in the 1980s and '90s.
The suicide bomber, Taimour Abdulwahab, killed himself and injured two people when some of the explosives he was wearing exploded among panicked Christmas shoppers in downtown Stockholm.
Police suspect the explosives went off by mistake too early, and that he had planned to detonate them in a more crowded place like a shopping center or train station.
One theory is that Abdulwahab had a problem with the equipment and walked off a busy pedestrian street to a side street to fix it "and that's when something happened," Thornberg said.
An audio file sent shortly before the blast from his cell phone referred to Sweden's military presence in Afghanistan and an image by a Swedish artist that depicted the Prophet Muhammad as a dog, enraging many Muslims.
Anti-Muslim bloggers said the bombing came as no surprise, heaping blame on Sweden's generous immigration policy. Tens of thousands of people from the Middle East, Somalia and the Balkans have fled to Sweden in the past two decades. No Western country admitted more Iraqi refugees amid the bloodshed following the U.S.-led invasion in 2003.
Integration is slow. Immigrants are clustered in suburbs of the big cities where few ethnic Swedes ever set foot. Surrounded by countrymen and other immigrants, many in those neighborhoods struggle to learn the Swedish language and to enter the job market.
A survey of 9,000 people by the SOM institute at Goteborg University earlier this year showed more than one-third of Swedes believe the country has admitted too many immigrants. Still, criticism of the immigration policy was rare until the Sweden Democrats broke through onto the national stage this year, winning nearly 6 percent of votes in the Sept. 19 election.
Hours after the bombing, Sweden Democrats lawmaker William Petzall wrote "I hate to say it, but we told you so," on his Twitter account.
"Is this the time when you're allowed to say: 'I told you so'? finally," said another tweet from party leader Jimmie Akesson's secretary, Alexandra Brunell. She later apologized, saying the wording was unfortunate.
The attack should serve as an "awakening" for Swedes, party lawmaker Kent Ekeroth wrote on his blog.
"What I mean is that people's attitudes about what Islam is and stands for are naive," Ekeroth told The Associated Press. "When finally there's been a terror attack on Swedish soil, then maybe people will understand. It's unfortunate that this is what it takes."
Similar views were being expressed by smaller and more extreme groups in Sweden, said Daniel Poohl, chief editor of Expo, a magazine devoted to exposing and counteracting ultranationalist and white-power movements in Sweden.
"This becomes a very clear example for them to point to and say 'This is what will happen if we don't stop immigration,'" Poohl said.
Leaders of Sweden's estimated 300,000 Muslims were worried about a backlash. The head of an Islamic Center in the southern city of Malmo, Bejzat Becirov, said he received hate mail on Thursday that he is handing over to police.
"The envelope said 'Merry Christmas.' And when I opened it there was a picture of a pig inside," Becirov told AP. It also contained a message about "exterminating" Muslims and profanity that "makes you sick."
On Dec. 31, a shot was fired into an office inside Islamic Center, ricocheting off a flower pot and narrowly missing the people inside, Becirov said. Police have linked that attack to an alleged serial gunman who opened fire randomly at immigrants, killing one person and injuring seven in a yearlong shooting spree.
A 38-year-old Swede was arrested in the case last month.
Faid Issa, a 23-year-old Somali-born Swede who studies sociology at Stockholm University, said he saw a difference in how Sweden reacted to the serial shooter and to Saturday's suicide bombing.
"Ethnic Swedes weren't blamed for what happened in Malmo," Issa said. "But Muslim immigrants are expected to distance themselves from the guy who blew himself up in Stockholm."
A terror attack does not necessarily trigger a backlash against Muslims. No such effect was seen in Spain in 2004 or in Britain in 2005 after terror attacks.
But in the Netherlands, long considered a bastion of tolerance toward religious and other minorities, attitudes toward Muslims hardened significantly after the 2004 murder of filmmaker Theo van Gogh, who was shot and stabbed on an Amsterdam street by an Islamic radical.
In Dutch elections this year, the anti-Islam "Freedom Party" led by Geert Wilders emerged as the country's third-largest political force and is now supporting a minority conservative coalition government. The party had campaigned to ban the burqa, cut immigration and imprison illegal aliens.
Analysts say it's too early to say which direction Sweden will take.
Those hostile to Muslims and immigrants "are likely to advance their positions after what happened," said Helene Loow, a Uppsala University expert on Sweden's extreme-right. "But the effects of this will only be visible in the long term."
Associated Press writers Malin Rising in Stockholm and Michael Corder in Amsterdam contributed to this report.