An increasing number of public figures are calling for Edward Snowden to be offered asylum in Germany, with more than 50 asking Berlin to step up it support of the US whistleblower in the new edition of Der Spiegel magazine

Heiner Geissler, the former general secretary of Angela Merkel's Christian Democrats, says in the appeal: "Snowden has done the western world a great service. It is now up to us to help him."

The writer and public intellectual Hans Magnus Enzensberger argues in his contribution that "the American dream is turning into a nightmare" and suggests that Norway would be best placed to offer Snowden refuge, given its track record of offering political asylum to Leon Trotsky in 1935. He bemoans the fact that in Britain, "which has become a US colony", Snowden is regarded as a traitor.

Other public figures on the list include the actor Daniel Brühl, the novelist Daniel Kehlmann, the entrepreneur Dirk Rossmann, the feminist activist Alice Schwarzer and the German football league president, Reinhard Rauball.

The weekly news magazine also publishes a "manifesto for truth", written by Snowden, in which the former NSA employee warns of the danger of spy agencies setting the political agenda.

"At the beginning, some of the governments who were exposed by the revelations of mass surveillance initiated an unprecedented smear campaign. They intimidated journalists and criminalised the publication of the truth

"Today we know that this was a mistake, and that such behaviour is not in the public interest. The debate they tried to stop is now taking place all over the world", Snowden writes in the short comment piece sent to Der Spiegel via an encrypted channel.

As calls for drastic measures in response to the NSA revelations are increasing in Germany, Angela Merkel seems to be avoiding direct confrontation with Washington. Several politicians from the chancellor's party have expressed their eagerness to meet Snowden in Russia while simultaneously seeming to rule out the possibility of inviting the whistleblower to Germany. "There is no reason to make a call on a Snowden stay in Germany at this stage," Michael Grosse-Brömer told Rhein-Neckar-Zeitung.

The Kremlin has signalled that it would allow German delegates to meet Snowden in Moscow. Snowden was free to meet anyone and would not be stopped from doing so, said a spokesperson for Vladimir Putin.

During a meeting with a politician from the German Green party in Moscow on Thursday, however, Snowden reportedly expressed reluctance about such a solution. Testifying to a German parliamentary inquiry in Russia, where his asylum runs out next June, would get the whistleblower nowhere nearer to solving his current dilemma. If Snowden left Russia to testify to the Bundestag, he would lose his current status but could potentially apply for asylum in Germany.

Meanwhile, signs are increasing that Merkel is trying to resolve the current diplomatic crisis with a new bilateral agreement with the US, instead of pushing for a pan-European reform of data protection laws. Frankfurter Allgemeine Sonntagszeitung reported on Sunday that the two countries were close to a "no spy" agreement, which is expected to be signed at the start of the new year. A delegation of German politicians visited the White House for discussions last week.

There is some speculation as to whether Merkel is using the crisis to try to negotiate German membership of the "five eyes" group – the intelligence-sharing network between America, Britain, Canada, Australia and New Zealand created during the second world war. Last week, Merkel's spokesperson denied Germany had intentions to join the anglophone club.