Germany's national security council has approved a deal to sell three further nuclear-capable submarines to Israel, magazine Der Spiegel reported on Friday, the latest act in a defense deal that has been overshadowed by corruption allegations.

The $1.5 billion transaction came to public attention when it emerged that shipbuilder ThyssenKrupp Marine Systems' Israeli intermediary had retained Prime Minister Benjamin Netanyahu's personal lawyer to act on his behalf.

The deal is now being scrutinized by authorities in both countries. The paper said Germany had inserted a clause into the contract giving it the right to tear it up if corruption allegations were proven.

Der Spiegel gave no source for its information. Ministry officials were unable to comment immediately.

Israel already has five submarines of the Dolphin Class, which can be equipped with nuclear warheads. A sixth is being built. Germany has agreed to finance a third of the costs of the contract.

In February, Israel's Justice Ministry, while not naming any suspects in the investigation, said there was no evidence that Netanyahu was involved.