The US is seeking to bring Iranian oil exports to zero. But Iran has a lot of experience in dodging international sanctions, having been under some form of embargo for decades.
In the past year, new sanctions from Washington warned off most of Iran's oil buyers and its sales plummeted. But, figures show that it is again beginning to rise a bit. So how exactly does Iran avoid US sanctions?
The answer is ghost ships – tankers try to hide their origin and destination by switching off their location transponders. When they go dark, they load cargo at ports, carry out ship-to-ship transfers and otherwise try to make it impossible for anyone watching to be sure where the oil came from or went.
But who is watching? Other than the US there are a growing number of tanker trackers. There are now several companies monitoring and watching the world's oil exports to give markets better information and data. The international community has used this evidence to try and show when countries are not enforcing international measures.
But amid this background of an uptick in Iranian ghost ships, another case has stood out.
On July 4, British royal marines stormed the Grace 1, a Panama-flagged Iranian vessel suspected of travelling to Syria in contravention of European sanctions.
Eight years into the brutal civil war, this is the first of many Iranian shipments to Bashar Al Assad that we know of being stopped.
So this week, Beyond the Headlines explores how Iran ships oil to Syria and also avoids American sanctions.
We speak to Samir Madani, co-founder of shipping monitoring website TankerTracker.com, who spends his days watching the world’s oil supply on the high seas. We also speak to Robin Mills, a UAE based oil expert and founder of Qamar Energy, to talk about Iranian exports and the impact of US sanctions.
For more on recent US-Iran tensions and the attacks on tankers in the Gulf region, check out our episode from a few weeks ago.