Iran is reportedly unable to locate naval mines it had deployed in the Strait of Hormuz, according to a New York Times report citing U.S. officials. The mines were placed by Iran to block the strategic waterway following the outbreak of war with the United States and Israel. Because the exact locations of the mines are unknown, Tehran has not been able to fully reopen the strait to maritime traffic.

The Strait of Hormuz handles nearly one-fifth of the world’s oil supply, making the situation particularly sensitive. U.S. officials said Iran did not maintain a complete record of where the mines were placed, and some may have drifted from their original positions. The Islamic Revolutionary Guard Corps had earlier warned that ships could collide with sea mines, though an alternate route was reportedly kept open for vessels paying tolls.

The uncertainty over the mines’ locations is also complicating ongoing peace talks in Islamabad, where discussions involve Iran’s assets and a potential ceasefire in Lebanon.