Taking a tough line on the bribery scandal that has shaken conglomerate Siemens, Germany's top appeal court ruled Friday that it was a crime to set up a slush fund.

It instructed a lower court to hear anew a case against two executives who misappropriated corporate money to bribe managers at Italian electricity company Enel into buying Siemens power equipment.

The ruling was part of the German legal system's toughening stance towards corporate corruption and may lead to harsher sentences on the two men. The trial court had believed it was a crime to pay a bribe, but not to set aside the money in corporate coffers to do so.

Investigators have discovered that Siemens executives hid 1.3 billion euros (1.9 billion dollars) in invisible accounts, also known as slush funds, for illegal purposes including corruption.

The ruling was the first from the federal high court in the justice capital of Karlsruhe on any of the Siemens cases.

The verdict Friday involved a Siemens turbines executive who forwarded 6 million euros in bribes in 2000 to Enel staff.