STOCKHOLM: Two blasts rocked the center of Stockholm Saturday night in what Sweden's foreign minister called "a terrorist attack," killing one person and wounding two.

The blasts Saturday took place after Swedish news agency TT said it received a threatening letter about Sweden's military presence in Afghanistan and a years-old case of caricatures of the Prophet Mohammad.

Asked if a man found dead at the site of the second blast blew himself up in some way, police spokesman Kjell Lindgren said: "It is possible."

The incident began when a car burst into flames in the city center, followed by explosions from within the car which the police said were caused by gas canisters.

Another explosion took place, in which the man died, about 300 meters (yards) away. Two people were wounded in that blast.

"Most worrying attempt at terrorist attack in crowded part of central Stockholm. Failed - but could have been truly catastrophic," Foreign Minister Carl Bildt said in a message on Twitter, which was also shown on his blog.

Investigations were underway to see if the two incidents were linked, Lindgren said.

Several hours after the blast, the man's body was still lying on the pavement, covered with a white sheet.

Police vans had cordoned off several streets around the body and the car had been towed away. Elsewhere, the city center was calm, with people having a normal Saturday night out.

Swedish newspapers all said the man did blow himself up.

Dagens Nyheter quoted a man called Pascal, a trained medic, as saying, "It looked as if the man had carried something that exploded in his stomach."

"He had no injuries to the face or body in general and the shops around were not damaged."

Newspaper Aftonbladet quoted a source as saying that the man was carrying six pipebombs, of which only one exploded.

THREATENING LETTER

He also had a rucksack full of nails and suspected explosive material, the newspaper said. It also quoted eyewitnesses saying the man was shouting in what was apparently Arabic.

The police declined to comment on that report.

TT said the email it received was also sent to the Security Police, which confirmed it had received such a communication, but declined to reveal its contents.

TT said the email had sound files in Swedish and Arabic.

"Our actions will speak for themselves, as long as you do not end your war against Islam and humiliation of the Prophet and your stupid support for the pig Vilks," TT quoted a man as saying in one of the recordings.

TT said the threat was linked to Sweden's contribution to the US led Nato force in Afghanistan, where it has 500 soldiers, mainly in the north.

It also referred to caricatures of the Prophet Mohammad by the Swedish artist Lars Vilks in 2007.

In March, an American who called herself "JihadJane" was charged with plotting to kill Vilks. In May, arsonists tried to set fire to his house.

Vilks, contacted by Reuters Television, was safe.

"This is the first casualty of my project," he said. "It was an act against the Swedish people to scare them and not to me. The good news was that a terrorist died and not someone else."

Evan Kohlmann, a US terrorism consultant, told Reuters that a small militant Islamic community had been based in Sweden for some time. But she thought that the Saturday incident, if an attack, was one man's work.

"However, given the scale of this attack and the target, I suspect this is a homegrown local extremist who may or may not have connections to any actual terrorist organization."

"We've seen a flurry of attempted attacks across northern Europe by similar lone wolf militants who were, in one way or another, enraged by the Cartoon controversy."

Lindgren said it was not clear what caused the car to explode. After the first explosion, the gas canisters caused smaller blasts, he said. – Reuters