Iran's Islamic Revolutionary Guard Corps said two tankers exploded after entering a mined route south of the Strait of Hormuz, a claim the US military denied.

In its 26th wartime statement, the IRGC said the vessels caught fire after being lured into the minefield by what it called deception on the part of American intelligence agencies. It did not identify the tankers, give their flags or say whether there were casualties, and warned other vessels to stay out of the mined corridor to protect their crews and cargoes.

The IRGC Navy said the strait was severely unsafe and completely closed as a result of American military action, and that no chemical fertiliser and not a drop of oil or gas would leave the region until US attacks on Iran end.

US Central Command rejected the account, saying the claim was false, in keeping with what it described as a pattern of fabricated IRGC announcements.

The Guard separately claimed its forces had halted four ships attempting to transit the strait in a combined missile and drone operation. Attacks on commercial shipping have continued through the week: the UK Maritime Trade Operations agency said a tanker was struck by a projectile off the coast of Oman overnight on July 17.

The strait has been effectively closed since the war began on February 28, when US and Israeli strikes on Iran prompted Tehran to begin targeting vessels in the waterway.

Iran has told tankers and cargo ships to use only channels close to its own coastline in the north of the strait, steering them away from the southern corridors near Oman where it says mines have been laid.

The mining claim lands amid a battle for control of the chokepoint. The US has reimposed a naval blockade of Iranian ports and has struck coastal missile, drone and naval targets for seven consecutive nights, while Tehran agreed under a June 17 interim deal to suspend its planned transit toll for 60 days, an arrangement now in effect abandoned by both sides.

Oil markets have priced in the disruption. Brent traded above $84 per barrel and was heading for a weekly gain of more than 10%. Roughly a fifth of the world's oil passed through the Strait of Hormuz before the war began.