The unnamed representative of the Bundesnachrichtendienst (BND) said that sharing mobile numbers with foreign agencies was a legitimate function of the intelligence service. However, he added that the agency only shared such information on the condition that it would not be used toward the death or torture of suspects.

Data would not be passed on if the "legitimate interests of the person concerned outweighed the public interest of the transmission," the representative said, adding that the numbers were "not suitable for accurate localization" of suspects.

The representative confirmed a report by the Süddeutsche Zeitung newspaper (SZ) and the Norddeutscher Rundfunk radio station's "Panorama" magazine alleging the BND passed such information on to the United States for years, putting the starting point at around 2003 or 2004. According to the representative, the policy has not changed since Gerhard Schindler took over the agency at the end of 2011.

'Targeted killings'

The SZ has put forth the case of a German citizen killed in a US drone strike in Pakistan's Waziristan region in 2010. It has emerged that German authorities shared the mobile numbers of the suspect and his friends with their US counterparts.

The opposition Social Democrats (SPD) and the Left party have asked for a complete clarification as to whether such information might have been used to locate the targets of drone strikes.

"It would be bad if the BND had contributed to such killings," the SPD politician and parliamentary intelligence committee chairman Thomas Oppermann said on Saturday, calling drone strikes "targeted killings outside of international law governing armed conflict."

Despite the BND's denial of such accusations, experts have said that a telephone number alone could be enough to locate a suspect. For example, Hannes Federrath, a computer science professor from Hamburg, told the SZ that data collected over a longer time period could be used toward just that end.

mkg/mz (AFP, dpa, AP)