A top US official said Tuesday that a deal with Iran to reopen the Strait of Hormuz could be struck "today or tomorrow", sending oil prices tumbling on hopes of increased shipments through the vital waterway.US Treasury Secretary Scott Bessent told CNBC "there is a chance we may have a deal" in the coming hours, echoing President Donald Trump.

Speaking from the White House on Monday, Trump kept up his familiar combination of optimism for diplomacy and threats, warning that this was Iran's "last chance before decapitation".

Tehran and Washington have been at war since Feb. 28, when the US and Israel launched surprise attacks on Iran. Despite a ceasefire and a preliminary deal in the months since, diplomacy has failed to end the conflict.

Underlining the volatile situation, one crew member was listed missing Tuesday on a merchant ship hit by a projectile in Hormuz, while an Indian ship in the Red Sea sank following an unattributed attack.

The Strait of Hormuz, a key conduit for global oil and gas supplies, has been the spark for renewed fighting.