LONDON (Reuters)- Security experts say suspicion is likely to fall on both Islamists and right-wing extremists following a deadly bombing and a shooting at a political gathering in tranquil Norway.
It was not clear if the attacks were linked, but the possibility of a complex, hybrid assault made it difficult to make an early call as to the likely political orientation of the assailants, security experts said.
A big bomb damaged Norway's main government building in the capital Oslo on Friday and police said seven people were killed and two badly wounded. There was no claim of responsibility.
Shortly afterwards, reports in local media came through of a shooting incident at Utoeya, an island south of Oslo where Prime Minister Jens Stoltenberg's Labour party youth section's yearly gathering was taking place. Daily newspaper VG said on its website a man dressed as a policeman was shooting wildly and had hit many people.TV2 said several people were killed. Bombings in city centers and marauding guns attacks are both tactics that have been used by Islamist militant gangs in recent years, mostly notably by al Qaeda-aligned guerrilla groups in Asia.
But in one unconfirmed report, the London-based Exclusive Analysis risk consultancy said the man in the shooting incident apparently infiltrated the party gathering on the pretence that he had been sent by the police as a security measure in the wake of the Oslo explosion.
"As such, it is likely he was ethnically Norwegian. This could indicate the involvement of a far-right group rather than an Islamist group, though it is also the case that the Labour Party would be a favorable target for Islamist groups due to its role in authorising Norwegian military deployments in Afghanistan," it said.
NATO member Norway has been the target of threats, if not bombs, before, notably over its involvement in conflicts in Afghanistan and Libya.
But Exclusive Analysis said there were no known domestic militant groups in Norway with the capability to stage large car bomb attacks.
The attacks happened just over a year after three men were arrested on suspicion of having links to al Qaeda and planning to attack targets in Norway.
Violence or the threat of it has already come to the other Nordic states: a botched bomb attack took place in the Swedish capital Stockholm last December and the bomber was killed.
Denmark has received repeated threats after a newspaper published cartoons of the Prophet Mohammad in late 2005, angering Muslims worldwide.
If Islamist militants are eventually found to be responsible, it would be the first such attack to have killed victims in Europe since suicide bombings in London killed 52 people in 2005.
"We need to be cautious because so little is known, but a bombing of this sort is either the work of far-right or Islamist militants," said Majeed Nawaz, who heads Britain's Quilliam counter-extremism think tank.
"Of the two, Islamists are the more likely."
A prominent militant propagandist called the bombings a "lesson" for other European countries and speculated that extremists were behind the attack, according to the SITE terrorism monitoring service.
In a message posted on the password-protected Shumukh al-Islam forum, the militant, who writes under the name of Abu Suleiman al-Nasser, said that the Oslo bombings are "another message arriving in the countries of Europe from the mujahideen (holy warriors)."
Al-Nasser has made several threats to European countries participating in the war in Afghanistan, SITE said.
Another posting by a participant called Emir Grozny said: "Threat against the Prime Minister of Norway. You have only moments to withdraw your soldiers from the grave of Khurasan and if not... you will see blood running in the streets."
However, the fact that the message was posted after the event means it cannot yet be confirmed if this individual had any relation to the attack, Exclusive Analysis said.
Security experts said Western intelligence agencies will be monitoring militant online discussion forums like Shumukh and the phones and emails of known militant sympathizers and suspects to detect clues to the identity of the perpetrators.
They will also be likely to be monitoring right-wing extremists, some said.
Anna Murison of Exclusive Analysis said Norway was not a priority country for jihadists, and any al Qaeda targeting of Norway would probably be opportunistic, based on the fact that it had happened to recruit a Norwegian.
"We also assess that any plans for spectacular attacks in Western Europe would probably have been altered or put on hold following (Osama) bin Laden's death, pending internal security reviews," she said, referring to the killing of the al Qaeda leader in a U.S. raid in Pakistan in May.
"A further possibility, therefore, is that the attack was led by Norwegian jihadist sympathizers acting on their own initiative, possibly after receiving basic training from jihadist groups overseas."
NATO member Norway has sometimes in the past been threatened by leaders of al Qaeda for its involvement in Afghanistan.
But political violence is virtually unknown in a country known for sponsoring the Nobel Peace Prize and mediating in conflicts, including in the Middle East and Sri Lanka.
It has also taken part in the NATO bombing of Libya, whose leader Muammar Gaddafi has threatened to strike back in Europe.
In a July 2010 article in the Atlantic magazine, Norwegian academic Thomas Hegghammer, one of the world's leading scholars of Islamist extremism, cited three possible reasons why "international good guy" Norway was of interest to al Qaeda.
The article, co-authored with political scientist Dominic Tierney, said Afghanistan and the cartoon issue were possible factors.
Norway has been in the International Security Assistance Force in Afghanistan from its foundation in late 2001. And in early 2006, a small Norwegian newspaper angered many Muslims by reprinting Danish cartoons depicting the Prophet Muhammad.
A third possibility was Norway's placing under house arrest of an Iraqi Kurdish Islamist, Mullah Krekar, a onetime leader of a guerrilla group, Ansar al-Islam. However, there was little or no evidence that al-Qaeda cared enough about Mullah Krekar to seek vengeance, Hegghammer and Tierney said.
"It may be pointless to search for a single grievance to explain the recent plot. Most likely, a combination of factors placed Norway on the jihadists' radar. In al-Qaeda's binary worldview, Norway is part of the 'Jewish-Crusader alliance' -- not a platinum member, perhaps, but a member nonetheless. If you're not with al-Qaeda, you're with the United States."
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