The Islamabad talks broke up after ~21 hours with no agreement. Within hours, Washington answered with a naval blockade of Iranian ports, effective 10am ET, run by CENTCOM under Adm. Brad Cooper. Over 10,000 personnel and more than a dozen warships are enforcing it. The cordon applies only to vessels sailing to or from Iranian ports, not third-country traffic in the wider Gulf.
For 45 days the constraint ran one direction: Iran shut Hormuz to hostile shipping. Now there is a second cordon facing the other way. The US Navy is sitting on Iran’s own export terminals. Kharg Island, which moves ~90% of Iranian crude, has buyers it cannot legally reach and a sea lane it cannot legally use. This is the dual blockade, and every laden Iranian barrel inside the Gulf is now stranded tonnage.
In the first 24 hours, per CENTCOM, no vessel attempted to run the line and six commercial ships complied with redirect orders. Crude snapped higher on the headline: Brent for June settled ~$99.36 (+~4%) and WTI for May ~$99.08 (+~2%), reversing the ceasefire-week slide as the failed talks plus a fresh blockade priced a longer closure.
Watch: Whether any Iranian-flagged tonnage tests the cordon; the shadow-fleet vessels now boxed in off Kharg and Bandar Abbas; Chinese and Indian reaction to a blockade of their sanctioned supplier; and whether the dual blockade hardens into a longer siege or becomes leverage for the next round of talks.