U.S. exports to Iran rose by nearly a third this year, chiefly because of grain sales, according to U.S. data released last week, despite the tightening of U.S. financial sanctions, Reuters reported.

The jump to $199.5 million in the first eight months of 2012 from $150.8 million a year earlier, according to Census Bureau data, is surprising given Western efforts to isolate Iran economically because of its suspected pursuit of nuclear arms.

The increase masks a drop in the export of some humanitarian goods such as medicines, a decline U.S. exporters blame largely on the difficulty of getting paid by Iranian importers because of new U.S. financial sanctions. Read more.