A Middle East-born man who died in a blast in Stockholm was wearing an explosives belt and likely intended to attack a crowded train station or department store when the device went off prematurely, an official said.
Police were all but certain the attacker was Taymour Abdulwahab, who emigrated to Sweden in 1992 but mostly lived in Britain with his wife and two children.
A militant who first identified Abdulwahab in an online message that included his photograph on Sunday issued a new statement on Monday warning of more such attacks if Western troops did not withdraw from Afghanistan.
'Battle of Stockholm'
"The battle of Stockholm is the start of a new era in our jihad, when Europe will become the arena for our battles," the Arabic-language message said, according to a translation by Flashpoint Partners, a U.S.-based service that tracks publications by militant groups.
The message, also monitored by another Islamist militant monitoring service, the Site Intelligence Group, added: "Those who insist on not heeding our demands must expect our attacks, which will reach the heart of Europe."
There was no way of independently confirming that the speaker had links to Abdulwahab but intelligence services were expected to study it for clues about ties to a militant network.
If he was, such a group could be plotting other bombings.
Interviews with people who knew him painted a portrait of a bubbly, fun-loving man who became increasingly radical in his views in Britain, and fell out with a local mosque there in 2007 over his extreme political opinions.
The attack, the first of its kind in Sweden, has heightened fears about attacks in Europe during the Christmas holidays.
The incident began when a car containing gas cylinders blew up in a shopping area in central Stockholm on Saturday. Minutes later a blast nearby killed the bomber and hurt two people.
"He was wearing a bomb belt and was carrying a backpack with a bomb," chief prosecutor Tomas Lindstrand told reporters.
"He was also carrying an object that looks something like a pressure cooker. If it had all exploded at the same time, it could have caused very serious damage," he said.
"It is not a very wild guess that he was headed to some place where there were as many people as possible, perhaps the central station, perhaps Ahlens (a department store)."
"It is not a very wild guess that he was headed to some place where there were as many people as possible, perhaps the central station, perhaps (department store) Ahlens, Lindstrand said.
Accomplices?
Lindstrand said the man was almost certainly Abdulwahab, who has been widely named in media, and that he assumed there had been accomplices, as the attack was well planned.
Justice Minister Beatrice Ask said the U.S. Federal Bureau of Investigation had sent seven bomb experts to help in the enquiry, the TT news agency said.
Lindstrand said Abdulwahab came from a Middle Eastern country, although it was unclear which. An entry by Abdulwahab on a Muslim dating website gave his birthplace as Iraq.
The Swedish immigration service said he had come to Sweden in 1992 and got citizenship six years later.
He studied at a university in the southern English town of Luton and graduated in sports therapy in 2004.
Luton is home to a large Muslim community, and was the place where the suicide bombers behind a deadly July 2005 attack on London's transport system met to begin their operation.
A British official who spoke to AP on condition of anonymity because of the sensitivity of his work would not comment on whether Abdulwahab had been on the radar as a suspected terrorist. But he said all threats stemming from controversial cartoons of the Prophet Muhammad — cited by the suspect as a motive for the attack — were being closely investigated.
British connection
Meantime, British police were searching a house in Luton in southern England where Abdulwahab was reported to have spent time.
"Officers executed a search warrant under the Terrorism Act 2000 at an address in Bedfordshire. There have been no arrests," a police spokesperson told . "We are confirming that this is in connection with the incident in Stockholm."
Also, SkyNews reported that Abdulwahab worshiped between 2006 and 2007 at a mosque in the British city of Luton but was expelled because of his extremist views.
Shortly before the blasts, Swedish news agency TT received a threatening letter criticizing Sweden's troops in Afghanistan, caricatures of the Prophet Mohammad drawn by a Swedish cartoonist and which spoke of a Middle East trip for "jihad."
Lars Vilks, whose 2007 depiction of the Prophet Muhammad has drawn regular threats from extremists, told The Associated Press he was shocked that suicide bombings have come to Sweden.
"It's a little unreal that we have such a case here," he said, adding that police had increased their presence outside his home following the botched attack.
The blasts follow several nervous months in Europe after a U.S. travel alert about possible attacks by militants and a failed bid by a Yemen-based al Qaida group to use air cargo to send parcel bombs via Europe to America.
The Stockholm incident began when a car burst into flames near an area busy with Christmas shoppers in the center of town, followed by explosions inside the car caused by gas canisters.
The second explosion was about 300 yards away and 10-15 minutes later, killing Abdulwahab and wounding two people.
Sweden's Department of Justice said that a team of FBI bomb experts had been dispatched to the Nordic nation to help analyze the explosives.
U.K. resident? A post on a Muslim dating website showed Abdulwahab was married with two young daughters and looking for a second wife.
In the post, he wrote that he was born in Baghdad and moved to Sweden in 1992 and that he studied at the University of Bedfordshire in Luton, a town with a large Muslim community.
The university confirmed that a student with his name and Swedish nationality graduated with a degree in sports therapy in 2004.
U.S. terrorism expert Evan Kohlmann told Reuters the suspect had been identified on online forums normally used by militant groups, including al-Qaida, as "holy warrior" Taimur Abdelwahab.
A Facebook page entitled "RIP (rest in peace) Taimour Abdulwahab our brother and friend" has been set up, Reuters reported.
Britain's interior ministry said it was in close contact with Swedish authorities but that it would be inappropriate to comment further.
The incident follows several nervous months in Europe after a U.S. travel alert about possible attacks by militants and a failed bid by a Yemen-based al-Qaida group to use air cargo to send parcel bombs via Europe to America.
German authorities last month said they were on guard against threats of armed attack on civilians of the kind that killed 166 in the Indian city of Mumbai in 2008, but Germany said on Sunday it saw no link with the Swedish attack.
TT said the letter promised attacks over Sweden's presence in Afghanistan, where it has 500 troops with the U.S.-led NATO force, and the cartoons drawn three years ago by Lars Vilks.
"This is a very serious incident, which is being investigated as an act of terrorism," Anders Thornberg, director of operations at the Security Police, said in a statement.
"As far as we know, it looks like he was working for himself, but we have to be really sure so we are investigating whether there could be more perpetrators," he told Reuters.
