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 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. "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.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.