(BSS/AFP) - Four tankers caught fire after hitting mines while attempting to navigate the Strait of Hormuz, Iran`s armed forces said Thursday, a day after the US military said it cleared key routes through the waterway.

"Over the past 24 hours, three violating oil tankers exploded and caught fire after striking mines while attempting to pass through the unauthorised southern route of the Strait of Hormuz," Iran`s Islamic Revolutionary Guards Corps said in a statement.

Later Thursday, Iran`s army reported that another tanker had caught fire east of the strait, after hitting mines while "operating in a restricted and dangerous area".

The initial three vessels had "switched off all their radar and navigation systems" and disregarded warnings from the IRGC navy, the statement said.

It was not immediately clear when the incidents occurred or which flags the tankers were flying.

British maritime agency UKMTO, meanwhile, said late Thursday it had received a report of a vessel on fire about 25 nautical miles (46 kilometres) northeast of Khasab, Oman, in the Hormuz strait.

Earlier, UKMTO reported two other incidents in the area: a dhow that caught fire and sank following a maritime security incident, and a tanker struck by an unknown projectile while transiting the Strait of Hormuz.

In recent weeks, Iran has reported multiple vessels striking sea mines, prompting US Central Command (CENTCOM), which runs military operations in the region, to reaffirm on social media its insistence that all mines in "primary transit routes" have been cleared.

On Thursday, Hossein Mohebi, the spokesman for the IRGC challenged the claim, saying on X: "Prove your Hormuz mine-clearing claim with independent evidence, not statements!"

Since the outbreak of the war on February 28, Iran has severely restricted traffic through the strategic waterway, which normally carries about one-fifth of global oil consumption.

The United States has in response imposed a blockade on Iranian ports and helped tankers travel the strait. On Sunday CENTCOM said it had helped Gulf countries export 1.5 billion barrels of oil via Hormuz since the summer.

Iran considers ships using the southern corridor near the Omani coast unauthorised.

In their statement on Thursday, the Guards said "the unauthorised route through the Strait of Hormuz is mined, and that vessel owners and crews are responsible for transiting these routes and should not pay attention to CENTCOM`s delusions on social media".

The IRGC also said it had captured a US reconnaissance drone, in a separate statement.

"The IRGC Navy announced that its electronic warfare unit had successfully captured a US MQM-170 drone during an offensive operation in the western Strait of Hormuz," the statement said.