Iran’s Islamic Revolutionary Guard Corps (IRGC) has warned that any ship approaching the Strait of Hormuz will face severe consequences. The warning came shortly after a US attack in Iran early Thursday, prompting Tehran to close the strategic waterway. The country’s top military command, Khatam al-Anbiya Central Headquarters, confirmed that the narrow passage has been completely shut down.

The IRGC Navy has instructed all oil tankers and commercial vessels currently operating in the Persian Gulf and the Sea of Oman to remain anchored. It stated that any movement toward the strait would be considered cooperation with the enemy. Citing a violation of ceasefire terms by US forces, the IRGC said the restriction will remain in place until further notice and urged ships to avoid the area for their own safety.

The IRGC described US forces in the region as a “terrorist army” and said the growing insecurity in the area necessitated the move. The Strait of Hormuz is one of the world’s most strategic chokepoints, through which about one-fifth of global petroleum supply passes.