Mohammed Salah is the head of the London-based Alhayat's Egypt office, and specializes in Islamic terrorist groups. Both he and his sources recognize the voice on the tape.

"It is definitely his voice. The accent is pronounced and known to me - like him I am born and grew up in Cairo," Salah said.

After speaking to sources in Afghanistan, Salah is certain the tape is genuine and likely a month old, made during the Iraq war, but he had not noticed that Norway was mentioned. Salah was also unsure what the message could mean, mentioning that Norway could be a camouflaged reference to an attack against a completely different target

t.

"Al-Qaida network members often attack targets that are completely different to official messages," Salah said.

Norway's PST (Police Security Service) have immediately begun investigating certain persons in Oslo's Muslim community that may have connections to the al-Qaida terrorist network.

The CIA (Central Intelligence Agency) has been granted authority to operate on Norwegian soil, reportedly because of dissatisfaction with earlier PST investigations, according to newspaper VG. The British secret service shall also have received expanded powers to operate in Norway. Norway's Justice Minister Einar Doerum Thursday rejected the idea that foreign intelligence have had their powers expanded.

The US embassy closed its doors to visitors Thursday after the latest terrorist message and is on full alert. American citizens "in need" will still receive assistance. The Ministry of Justice and Police said that security measures would be in place around selected embassies in Norway.

Justice Minister Doerum said that there was no reason for people leaving in Norway to feel at risk.

"Norwegians can go about life normally. They can expect authorities to do what they should to stay on top of the situation and implement important and necessary measures," Doerum told Norwegian Broadcasting (NRK) on Thursday morning.