The US military is maintaining a naval perimeter around Iranian ports through a maritime operation known as the "steel wall blockade." As of Sept. 23, US Central Command redirected 115 commercial vessels to ensure the blockade remains strictly enforced, according to a statement from the command.

The maritime restrictions coincide with a collapse in visible shipping through the Strait of Hormuz, where traffic dropped to three commodity vessels on Tuesday. This disruption has pushed the cost of hiring very large crude carriers from the Persian Gulf to Asia up more than 1,000% to a record $1.1 million per day, while the US spends over $30M daily to maintain the naval operation.