The U.S. Treasury Department is revoking the authorization for Iranian oil sales, a sharp policy reversal triggered by a fresh wave of attacks on tankers in the Strait of Hormuz.

A U.S. official confirmed Tuesday that the Office of Foreign Assets Control (OFAC) is withdrawing the general license that had permitted the sale of Iranian crude, effectively closing a key legal channel for Tehran’s energy exports.

Earlier this week, Brent crude had slid below $71 as traders reacted to advancing U.

The decision marks a significant escalation in the ongoing regional tensions, coming just days after markets had begun to price in a de-escalation.

Earlier this week, Brent crude had slid below $71 as traders reacted to advancing U.S.-Iran talks and easing supply fears in the chokepoint.

The revocation of the waiver, however, signals that diplomatic progress is fragile and that physical security risks in the Strait remain acute.

Recent attacks on three tankers have defied ceasefire expectations, spiking shipping risk and forcing insurers and operators to reassess route exposure.