The first full day of the United States’ naval blockade on Iranian ports left questions about its effectiveness. According to BBC security correspondent Frank Gardner, the uncertainty may stem from inadequate preparation and interference with ship transponders. BBC Verify’s analysis of maritime tracking data showed that at least four Iran-linked vessels, including two that had visited Iranian ports, crossed the Strait of Hormuz on Tuesday. Three other non-Iranian ships also passed through the strait after the blockade began at 10 a.m. US time on Monday.

US Central Command chief Admiral Brad Cooper stated that the blockade had been fully implemented, claiming that within less than 36 hours, US forces had completely halted all economic trade to and from Iran by sea. Earlier, the command reported that six commercial ships had turned back toward an Iranian port following US military instructions. However, BBC Verify data indicated that at least two Iran-linked vessels also changed course after crossing the strait.

The mixed signals between official statements and independent tracking data highlight ongoing uncertainty about the blockade’s real impact on maritime movement in the region.