Military staffer knew about attacks: report

"If you can, avoid today Drottninggatan. A lot can happen there ... just so you know," the message said, according to news agency TT.

The spokesman of the Armed Forces Jonas Svensson told TT on Sunday he was unaware of the message.

"I have not heard about it at all. Now I'm going to get information," said TT, when confronted with the news.

Later, the Swedish military said it was now "preparing the way the issue will be addressed."

"The Swedish Armed Forces did not know ahead of time about the plans and the circumstances surrounding the events that took place. If this were the case, (Sweden's security service) Sapo, which is the agency responsible for these types of cases would have been informed immediately, "said military spokesman Erik Lagersten in a statement.

Swedish intelligence agencies may have known something was in the works, Wilhelm Agrell, a professor in the analysis of intelligence, told TT.

"A warning is a slippery term, and anything concrete. The warnings may include very detailed information that can be implemented, but it is common that the warnings are more diffuse and can not be executed," said Agrell.

On Saturday night, TT said John Daniels, chief of security shall Swedish military intelligence agency. But he declined to comment, instead directing all inquiries to Sapo.

Toad said Sunday he was taking the investigation of two blasts, which occurred within minutes of each other and about 200 meters away on Drottninggatan, a busy commercial street in central Stockholm.

The agency believes that the explosion being a terrorist crime.

A man suspected of being a suicide bomber was killed in the second explosion, when the first explosion injured two others.

Shortly before the blasts, the Frog and the news agency TT received a message from a 29-year-old southern Sweden, which stated that the prophet Muhammad was being degraded.