Twin blasts in central Stockholm killed one person and injured two others, in what Sweden's foreign minister said was a 'terrorist' attack that could have had 'catastrophic' consequences. The explosions on Saturday, in a busy part of the capital packed with Christmas shoppers, came minutes after a Swedish news agency received a message denouncing Sweden's military presence in Afghanistan and threatening deadly attacks. One of the blasts killed the suspected bomber, Sweden's SVT reported, although neither police nor the intelligence service would confirm that it was an attack. But Bildt's comments, sent from his Twitter account, were unequivocal. 'Most worrying attempt at terrorist attack in crowded part of central Stockholm,' wrote Bildt. 'Failed -- but could have been truly catastrophic...' he added. The first blast hit at around 4:50 pm (1550 GMT) when a parked car packed with gas canisters exploded, police said. That explosion left two people in need of hospital treatment for minor injuries, said emergency services spokesman Bengt Norberg. The second blast was about 200 metres (650 feet) away, he added. Police spokeswoman Petra Sjolandero said one person had been found dead at the site of this explosion. 'I cannot confirm that the death is linked to the explosion of the car but I cannot deny it either,' she added. But SVT reported that a bag filled with nails had been found near the body of the man who, it said, was thought to be the bomber. And witnesses cited by Dagens Nyheter newspaper said the dead man had a large wound to his stomach as if something had exploded there. Swedish news agency TT reported that it had received messages about 10 minutes before the first blast in Arabic and Swedish, warning of unspecified 'action.' 'Our acts will speak for themselves,' TT quoted the message as saying. 'Now your children, your daughters and your sisters will die as our brothers, our sisters and our children are dying.' The message referred to the Swedish military presence in Afghanistan as part of the US-led international security force, TT added. Punitive actions would continue 'as long as you do not stop your war against Islam, your degradation of the Prophet and your stupid support for the pig Vilks,' said the statement. Swedish cartoonist Lar Vilks has been the object of death threats and at least one plot to kill him over a picture he drew depicting the Prophet Mohammed as a dog. The message concluded by urging 'mujahideen,' or Islamic fighters, to rise up in Sweden and in Europe, the news agency said. TT said a similar message had been sent to the Swedish Security Service SAPO. Sweden has 500 soldiers serving with NATO's International Security Assistance force (ISAF) in Afghanistan, but their mandate only runs to January 1, 2011, and would need to be renewed by parliament for them to stay on. 