German officials on Thursday closed their preliminary investigation into alleged spying by the US and UK intelligence services, announcing they would not seek criminal proceedings over the scandal.

The decision comes four years after whistleblower Edward Snowden accused the US National Security Agency (NSA) of massive breaches of privacy and illegal spying on Americans and citizens of many other countries around the world, including Germany. Notably, Snowden's documents revealed that the NSA was monitoring Chancellor Angela Merkel's private cell phone.

Read more: German intelligence 'spied on White House'

In 2015, however, German prosecutors dismissed that specific claim as "unprovable in a court of law."

On Thursday, the officials also said there were "no reliable grounds" for other accusations, such as that foreign intelligence services "illegally, systematically and massively monitor German telecommunications and internet traffic." Also, the Snowden-provided documents showed "no solid evidence about espionage activities in or against Germany," they added.

The data gathered in the preliminary inquiry shows the extent and the capabilities of the American spy agencies. However, there is no evidence to support that these capabilities are "aimed" against Germany, they said.

Earlier this year, a parliamentary committee presented a report on the spying issue, but the long-winded document provided little clarity. Opposition parties refused to sign off on it and complied a 450-page dissent, which the leaders of the investigative committee refused to publish.

Merkel also testified on the NSA spying affair before the Bundestag, where she said it was never proven that the Americans listened in on her phone conversations. At the same time, she denied having any deeper knowledge of German surveillance practices before 2015 and any responsibility for mistakes made by her subordinates.

The smaller German opposition parties in the outgoing parliament, the Greens and the Left party, have also repeatedly called for Edward Snowden to testify before the committee, but the move was blocked by the grand coalition of Christian Democrats and Social Democrats.

Read more: Merkel testifies on NSA spying affair

Spying among friends

The 2013 NSA revelations on the extent of NSA's spying in Germany shocked German public and sparked a diplomatic row between two close allies, with Merkel saying that "spying among friends" was unacceptable. However, the row was soon overshadowed by the Russian takeover of Crimea, which prompted western countries to present a united front.

The issue was also diluted by reports on the German Intelligence Agency (BND) spying on friendly governments, which surfaced in 2015. Earlier this year, Germany's Der Spiegel news magazine reported that the agency had been keeping tabs on White House staff between 1998 and 2006.

Germany's BND spy agency relies heavily on resources and tools supplied by its American aliles. The NSA reportedly provided German agents with spying software in exchange for data sharing. Also, the BND and it domestic intelligence couterpart BfV were accused of assisting the NSA in its global surveillance programs.

dj/rt (AFP, dpa, Reuters)