The first letter was sent to Norway's Ministry of Foreign Affairs on 27 June 2013, at the same time as Snowden was stranded at Moscow's Sheremetyevo airport waiting for Russia to grant him asylum.
The note reads: “We request that should US citizen Edward J. Snowden attempt to enter Norway through any means, the Government of Norway notify the Embassy immediately and effectuate the return of Mr. Snowden to the United States by way of denial of entry, deportation, expulsion or other lawful means”.
The FBI's regional office sent another letter the same day to the justice authorities of Norway, Sweden and Finland, describing Snowden as a criminal on the run and asking them to notify them should Snowden book a flight to one of their countries.
On July 4, the Norwegian Department of Foreign Affairs received another note, a formal request for the arrest and extradition of Snowden should he enter Norwegian territory.
“The United States urges that Snowden be kept in custody, if arrested,” the note reads.
In a note from the US embassy in Oslo, the US asked the Norwegian authorities to do everything in their power to seize anything which might contain the stolen files.
“The Embassy requests the seizure of all articles acquired as a result of the offenses (..) This includes, but is not limited to, all computer devices, electronic storage devices and other sorts of electronic media.”
Snowden's lawyer Ben Wizner told NRK that the most worrying aspect of he documents was the US's pressure on Norway and presumably other countries to arrest Snowden and extradite him, before he had had a chance to apply for asylum.
“What is troubling to me is the suggestion that if Mr Snowden showed up in one of these countries, he should be promptly extradited – before he would have a chance to raise his humanitarian rights under international law,” he said.
“The only correct response from political leaders in Norway or any other free society should be to tell the US that this is a question of law and not a question of politics. And that under international law, someone who is charged with a political offence, has a right to raise a claim for asylum before the question of extradition even comes up.”
According to the Justice and Foreign Affairs departments, Norway has yet to respond to the US requests, as under Norwegian law a country cannot request an extradition until the alleged criminal is on Norwegian soil.
Jøran Kallemyr, state secretary for the Department of Justice, said: “What Norway has done is to inform the American authorities how the Norwegian system works,” he said. “If they request an extradition, the prosecuting authorities will decide if the case should be brought before the courts. And the court will decide if the terms for extradition are fulfilled.”