The amendment follows intense lobbying of the German government and the central bank by the U.S. to stop the Islamic Republic from claiming the assets in what U.S. diplomats think is a desperate scramble to boost Iran’s foreign reserves and shore up its own currency after Washington pulled out of the Iran nuclear deal.

Effective August 25, the amended rules create new powers to block transactions if their execution could threaten “to end important relationships with central banks and financial institutions of third countries,” according to a copy of the rules provided by the Bundesbank on Friday.