The United States has revoked the general license that previously authorized the sale of Iranian crude oil, a decisive policy shift that removes a key outlet for Tehran's exports.
The move comes as geopolitical pressure intensifies in the Persian Gulf, following US military strikes on Iran earlier today in response to attacks on three ships in the Strait of Hormuz.
This action marks a significant escalation in economic pressure on Iran, coinciding with heightened military activity in the region.
Global energy markets reacted sharply to the dual shock of military strikes and the withdrawal of the export license.
Brent crude prices rallied as traders priced in the immediate risk of supply disruption from the world's most critical oil chokepoint.
The Strait of Hormuz, through which roughly a fifth of global oil consumption passes, is now facing compounded threats from both kinetic military action and renewed economic sanctions.