Four oil tankers were hit by explosions in the Strait of Hormuz, Iran's military said on Thursday, adding that the vessels had ignored warnings and entered what it considers restricted areas of the strategic waterway.
Tankers are still facing attacks across the strait, despite a rebound in traffic and expectations of a de-escalation in the war between the United States and Iran that have been reflected in falling oil prices.
Iran's Revolutionary Guards Navy said two supertankers were disabled by explosions on Wednesday after they ignored warnings against using what it said was an "unauthorised route".
Reuters could not immediately verify the Iranian account.
The two vessels, "exploded after hitting naval mines", Iranian state media reported, broadcasting what it said was video footage of the incidents.
Iran's army later said two other tankers had hit mines on Thursday afternoon while sailing through the eastern Strait of Hormuz after ignoring warnings and disabling their radar systems, state TV reported. The tankers entered a restricted area and subsequently caught fire, it reported.
Earlier in the US-Israeli war with Iran, which began in February, the IRGC Navy announced its attacks on tankers. More recently, however, it has instead reported that vessels have caught fire after hitting naval mines while traversing the southern part of the strait, which it has declared an unauthorised route.
In several of those cases, the United Kingdom Maritime Trade Operations agency (UKMTO) has said vessels had been struck by unknown projectiles.
The UKMTO said in reports on Thursday that a vessel was hit by an unidentified projectile about 14 nautical miles northwest of the UAE emirate of Ras Al-Khaimah on Wednesday while exiting the strait, causing a fire in its engine room.
Firefighting efforts were under way and all crew had been evacuated, it added.
At least 10 ships were hit in the first 10 days of November, after 37 attacks in October, which was the highest monthly tally since the conflict began in late February, according to data from the Washington Institute for Near East Policy.
(Reporting by Jana Choukeir and Elwely Elwelly; Additional reporting by Eman Abouhassira; Writing by Emily Giles; Editing by Louise Heavens, Tomasz Janowski, Michael Georgy and Joe Bavier)