American prosecutors have indicted a Chinese citizen for running a missile component related smuggling operation. The defendant shipped critical metals, like tungsten, used for making rocket components, to Iran. The defendant mislabeled scrap metal as stuff that was legal to sell to Iran. The U.S. is uncovering more of these Iranian smuggling operations, partly because more pressure is being brought on banks to report suspected cases of illegal arms (and weapons components) trading. The Chinese firms used American banks to create false company accounts, in order to hide the metal shipments from UN and U.S. officials enforcing the embargo.
Ever since the U.S. embargo was imposed in 1979 (after Iran broke diplomatic protocol by seizing the American embassy), Iran has sought, with some success, to offer big money to smugglers who can beat the embargo and get needed industrial and military equipment. This is a risky business, and American and European prisons are full of Iranians, and other nationals, who tried, and often failed, to procure forbidden goods. The smuggling operations are currently under more scrutiny, and attack, because of Iran's growing nuclear weapons program. But the Iranians simply offer more money, and more smugglers step up to keep the goodies coming.