The U.S. State Department declined comment. A spokeswoman for the UK Treasury said she could not comment on specific cases but added: "The government fully backs the tough regime of EU sanctions that have been put in place against Iran." The Dutch Economic Affairs Ministry did not comment.
"It's a pretty complicated transaction that needs three sets of government approvals for an exception to sanctions covering banking, insurance, shipping and dealing with a banned Iranian counter-party, NIOC," said Mark Dubowitz, the head of the U.S. Foundation for Defense of Democracies, which is a leading advocate of harsher sanctions on Iran.
"They'll be wary about whether this is precedent-setting for other companies that may be in debt to Iran."
This year's banking, oil, insurance and shipping sanctions have tightened the screw on Iran's finances, halving its oil exports and forcing a collapse in the value of the Iranian rial currency.
Sanctions do not apply to the delivery of grains and other foodstuffs but, isolated from international banking, Iran has been forced to pay a premium for grain imports. Grain traders expect it to end up buying about 5 million metric tonnes on the open market in 2012, some of that supplied by Cargill.
Grain worth $1.4 billion would be enough to meet about 80 percent of that annual import requirement, assuming a range of imports including wheat, corn and barley priced at about $300 a metric tonne with shipping.
That would provide a stopgap for the drain on Iran's dwindling foreign exchange reserves, which are thought to have dropped by tens of billions of dollars this year from about $100 billion at the start of the year.