Munich - Revelations that Siemens turbine salesman paid kickbacks to Italian electricity company Enel triggered military concern in Germany four years ago, corporate sources said Saturday.

The bribery to secure orders from Enel was part of a 1.3 billion-euro (1.9-billion-dollar) web of corruption that has plunged the German conglomerate into legal tangles, but it was not previously known that it threatened Siemens' defence secrecy clearance.

The sources confirmed a report to appear in Monday's issue of the news magazine Der Spiegel that the German military demanded an explanation.

Spiegel quoted minutes of a November 2004 Siemens board meeting that was briefed by corruption-buster Albrecht Schaefer about a defence ministry demand for a meeting about the company's rules compliance.

At the time, Siemens was tendering to supply computer and telephone systems to the German military, Spiegel said.

Spokesmen for the defence ministry declined to comment on the news report. A Siemens spokesman merely said it was normal for Siemens to discuss many matters with its customers.

Spiegel said Siemens had apparently managed to satisfy the defence ministry that it was clean, with a defence investigator being assured that staff who had paid bribes to Enel in 2000 had left the company.

Siemens was warned it faced security vetting if more corruption was revealed. For two more years there was calm. Then German prosecutors discovered there had been widescale bribery at the Siemens group. (dpa)