BERLIN (Reuters) - Germany's top public prosecutor closed a year-long investigation into the suspected tapping of Chancellor Angela Merkel's cell phone by U.S. spies, saying there was a lack of evidence that would stand up in court.
Dropping its probe in a case that had caused strains between Germany and the United States, the prosecutor said it could not find evidence backing allegations from former National Security Agency contractor Edward Snowden that Merkel's phone was bugged.
"The accusations made would not stand up in court with the means available for criminal proceedings," the federal prosecutors office in Karlsruhe said in a statement.
"The vague remarks from U.S. officials about U.S. intelligence surveillance of the chancellor's cell phone - i.e. 'not any more' - are insufficient evidence".
Merkel's spokesman Steffen Seibert declined to comment on the prosecutor dropping the probe.
"The federal prosecutor has made his decision," he said. "Such a decision should not be commented on by the government."
The two countries have been at odds over the NSA spying habits since Snowden's revelations last year showed the United States had listened in on many of its allies, including Merkel.
Federal Prosecutor Harald Range had launched the probe last June, saying there was preliminary evidence to show U.S. intelligence had tapped the phone. But he said at the time there was not enough clarity to bring charges.
In December, Range had signaled that the investigation was not going successfully, saying it had failed to turn up any concrete evidence.
"The document presented in public as proof of an actual tapping of the mobile phone is not an authentic surveillance order by the NSA," he said in December. "It does not come from the NSA database. There is no proof at the moment which could lead to charges that Chancellor Merkel's phone connection data was collected or her calls tapped."
Range also said neither a reporter for German news magazine Der Spiegel who presented the document, nor Germany's BND foreign intelligence agency, nor Snowden had provided further details to his office.
Snowden has sought refuge in Moscow. Merkel's government has shied away from bringing him to Berlin to testify to a parliamentary enquiry into the espionage, fearing it would further damage relations with Washington.
(Reporting by Erik Kirschbaum; Editing by Dominic Evans)