The US military has set up a unit to stop weapons, goods under sanction and other materials reaching Iran by land and across the Caspian Sea. Until now, Washington’s pressure campaign has focused on a naval blockade. Here is what we know about Task Force Iron Gate: Central Command (Centcom) chief Adm Brad Cooper ordered Task Force Iron Gate into being on Saturday. The force has about 20 civilian and military staff in Tampa, Florida and will work with other American agencies.