Four oil tankers have hit mines and caught fire while travelling through the Strait of Hormuz.
One was a "supertanker" carrying more than two million barrels of oil.
Oman said it had rescued 25 crew members from a tanker attacked in the Strait, without confirming whether it was one of those which hit a mine.
Iran's Revolutionary Guard says four oil tankers, including a "supertanker" carrying more than two million barrels of oil, have hit mines and caught fire while travelling through the Strait of Hormuz.
The IRGC said the tankers suffered explosions on Friday after attempting to use unauthorised routes through the strait.
The Guard's navy claimed the vessels had switched off their navigation and positioning systems and ignored repeated radio warnings. Iran's report did not identify the vessels or provide details about the crews.
Tehran has asserted control over much of the waterway since the US and Israel launched the war on February 28. ( AP: Razieh Poudat/ISNA )
Oman said it had evacuated 25 crew members from a Panama-flagged tanker that was attacked in the strait, 1.6 nautical miles off the coast of Musandam Governorate, catching fire. It is unclear whether that incident is related to the fires described by Iran.
The United Kingdom Maritime Trade Operations centre also reported on Friday that a vessel was struck by an "unknown projectile" south of Lavan, an island just off mainland Iran near Shidvar.
The British military organisation, which monitors maritime safety, said the crew was safe.
An Iranian official said two fishermen were missing and two others injured in an attack on two other boats in the strait, blaming the US.
Iran has repeatedly warned that vessels passing through the strait without Tehran's permission would face "destruction."
Tehran has asserted control over much of the waterway since the US and Israel launched the war on February 28.
Iran's supreme leader Mojtaba Khamenei on Saturday warned the United States and Israel against returning to war following threats from the Islamic republic's foes of a possible resumption of strikes.
The remarks came during a reported meeting between the supreme leader and senior military commanders, including armed forces chief of staff Ali Abdollahi, army chief Amir Hatami and Revolutionary Guards commander Ahmad Vahidi. It was the first reported meeting between them.
Supreme Leader Mojtaba Khamenei has not been seen since he was appointed at the beginning of the Iran war. ( AP: Vahid Salemi )
Mojtaba Khamenei has not been publicly seen since he became supreme leader, following his father Ayatollah Ali Khamenei's killing in US-Israeli strikes at the start of the war in February.
In his statement, the leader ordered commanders to meet any threat "with an immediate, impactful and geographically unrestricted response".
He also ordered commanders to update Iran's target list to include "all types of tangible and intangible assets belonging to the American-Zionist enemy".
The supreme leader's statement came amid fresh diplomatic efforts to avert a resumption of fighting.
A Qatari delegation arrived in Tehran on Friday for talks with Iranian officials, after Iran reportedly received a letter from US Vice President JD Vance.
According to Iranian media, Tehran had yet to respond to the letter.
