Berlin - The phone-tapping equipment which has allowed Iranian authorities to monitor protesters' mobile phone messages was exported by Germany without any government checks, the news magazine Der Spiegel reported Saturday.

The equipment, made by Nokia Siemens Networks, allows intelligence agencies to detect opponents' communications amid millions of calls, text messages and video clips.

Der Spiegel quoted the Finnish and German joint venture as saying it did a detailed review of the legal position before deciding not to apply for a clearance from the German agency which monitors arms exports.

The company said the intelligence equipment did not appear on any German list of dangerous exports, since its use was neither militarily useful nor connected to nuclear research.

Der Spiegel said the system was sold to Iran via Dubai.

US news reports have focussed on the system as a tool in the authorities' crackdown on the protest movement.

US accounts have suggested that a mysterious brief shutdown of the mobile phone system two weeks ago may have been the time when the mass monitoring system was hooked up and deployed.

Der Spiegel quoted German government sources saying neither Berlin nor the BND foreign intelligence agency were told of the sale. (dpa)