The Trump administration hopes the sweeping sanctions it has imposed on Iran's oil, shipping and banking industries will cripple its economy and force it to negotiate a new nuclear deal.
But analysts point out that while such economic penalties can be persuasive, there are also ways to circumvent them.
"There will always be both overt and covert activities to work around sanctions, to dodge sanctions or evade them," says Dan Wager, a global sanctions expert at the consulting firm LexisNexis Risk Solutions. "That's something that's gone on for a very long time."