A US missile struck an Iranian oil tanker near Iran's Kharg Island on Saturday, according to Iranian media.
The tanker involved was a "small vessel," Iran's Student News Agency reported.
It said no casualties were reported.
Kharg Island is vital to Iran's oil export system, handling roughly 90% to 95% of the country's crude exports.
US President Donald Trump previously threatened to take control of the island.
Regional tensions have escalated since US-Israeli attacks on Iran began Feb. 28, with Tehran responding with missile and drone strikes against Israel and US interests across the region.
Washington and Tehran signed a memorandum of understanding on June 18 concerning freedom of navigation through the Strait of Hormuz, but its implementation has stalled amid disagreements over security arrangements in the strait.
