Edward Snowden, former contractor at the US National Security Agency who is in exile in Russia after leaking millions of top secret intelligence documents to the media, is seeking a return to his home country.

Germany's Der Spiegel, citing Snowden's German lawyer Wolfgang Kaleck, reported that the whistleblower is "considering' returning to the US under certain conditions.

"There are negotiations," Kaleck told the news magazine.

"Those who know the case are aware that an amicable agreement with the US authorities will be most reasonable."

He noted there were efforts at least in the medium term to find a solution that is tolerable for Snowden. However, Snowden is not involved in the negotiations, according to the lawyer, who is also secretary-general for the European Centre for Constitutional and Human Rights.

Kaleck said his client had never acted selfishly and caused no damage.

"That's why, one could hope that a democratic US government paves the way back to him," he added.

At Kaleck's request, the NSA investigation committee in the German Bundestag, a constitutional and legislative body, is currently clarifying with the federal government whether Snowden can enter and testify in Germany.

The New York Times earlier reported that in the summer of 2013, Snowden was seeking the assistance of Washington DC-based attorney Plato Cacheris to negotiate a plea deal with federal prosecutors.

Snowden received international attention after he leaked up to 1.7 million top secret documents about the NSA's surveillance programmes.

The Obama administration faced severe criticism across the globe as the documents revealed that the NSA tapped telephone conversations and spied on the internet activities of prominent people, including German chancellor Angela Merkel and Brazilian president Dilma Rousseff.

Snowden is wanted by the US on charges of espionage and theft of government property.

Earlier, members of the Scottish parliament (MSPs) considered a call for the former NSA contractor, who is currently being sheltered in Russia, to be given political asylum in Scotland if voters opt for independence in September's referendum.

Campaigner Mick Napier, a former university lecturer, put forward a petition to the Scottish parliament's Public Petitions Committee, saying Snowden was owed a "debt of gratitude" for his actions and that hosting him would be an "honour for Scotland".