The UAE Ministry of Defense said on Monday that Iranian cruise missiles struck two Emirati oil tankers while transiting the southern lane of the strait in Omani territorial waters.
The United Kingdom Maritime Trade Operations agency said a tanker had been hit by an unknown projectile while travelling 40 nautical miles northeast of Oman's Qalhat.
Reuters could not immediately verify whether the UKMTO report referred to the same incident as the one reported by the UAE Ministry of Defense.
The IRGC said two "offending" supertankers had been hit and disabled in the strait after ignoring repeated warnings and turning off navigation systems, Iranian media reported.
The IRGC's statement did not name the vessels or say whether they were the same tankers cited by the UAE ministry. But it accused the U.S. of "inciting vessels to use an illegal route" and warned that cooperation with the "aggressor enemy" would result in damage, delays in reopening the waterway and a global energy crisis.
The U.S. Navy-led Joint Maritime Information Center said a blockade of Iran would take effect at 2000 GMT on Tuesday and apply to all vessel traffic regardless of flag, covering the entire Iranian coastline including ports and oil terminals.
It said the measure would not impede neutral transit passage through the strait to or from non-Iranian destinations, and that humanitarian shipments would be permitted subject to inspection.
The U.S. and Israel attacked Iran on February 28 and Iran responded with its own strikes on Israel and Gulf states that host U.S. bases. U.S.-Israeli strikes on Iran and Israeli attacks on Lebanon during the war have killed thousands and displaced millions.