Brent crude futures climbed $2.32, or 2.25%, to $105.40/bbl at 08:03 GMT on 24 September, according to Reuters pricing. US West Texas Intermediate (WTI) futures gained $1.78, or 1.93%, to $93.94/bbl.

What is driving the rally?

Two supply-side pressures anchored the move: a diplomatic freeze between Washington and Tehran, and a contested rumour of a US diesel export ban. US-Iran negotiations made little headway, officials from both governments told Reuters, after duelling speeches by Donald Trump and Masoud Pezeshkian at the UN General Assembly in New York.

Where do the negotiations stand?

The two sides exchanged peace proposals in recent weeks, the Iranian official said. Washington's offer includes calls for lifting the US naval blockade on Iranian ports and reopening the Strait of Hormuz. Tehran is reviewing the latest US response, a process the official suggested could take days rather than weeks.

A senior Iranian official told Reuters on 23 September that the two countries "remain far apart on how to end their war but diplomacy must continue". Iranian President Pezeshkian said Tehran would "never surrender to US pressure" and accused Washington of a "bullying mentality". Trump used the UN platform to threaten Iran.

Is the Strait of Hormuz still closed?

Yes. Iran's Security Council Chief Mohsen Rezaei said the chokepoint would stay shut while Tehran's conditions remain unmet. Iranian negotiators are reviewing Washington's response, which includes the unblocking of Iranian ports and reopening of the waterway.

Roughly a fifth of global seaborne oil transits the strait, making any sustained closure a fast path to refined-product rationing across Asia and Europe. The wider market read: little prospect of a diplomatic off-ramp before the next OPEC+ meeting and no relief for Middle East flows while the waterway stays shut.

Will Washington ban diesel exports?

The administration is weighing a 90-day diesel export prohibition, Reuters reported, a step that would tighten Atlantic Basin supply. The White House has publicly denied the plans. US Energy Secretary Chris Wright said on 23 September that a diesel export ban "would not work and could push up gasoline and jet fuel prices".

ULSD futures fell about 5% on 23 September once news of the proposal crossed screens, a move traders attributed to hopes of near-term easing in domestic prices should the curb take effect.

What does the inventory tape show?

US Energy Information Administration data show distillate inventories — diesel and heating oil — fell 428,000 bbl to 107.4 mbbl in the latest weekly report. Crude inventories climbed 3 mbbl to 426.4 mbbl, leaving refiners thin on middle distillates as the northern hemisphere heating season opens.

The combination of a distillate draw against a crude build shows US Gulf Coast and Midwest refiners pulling middle-distillate barrels toward home demand. Traders will look to the next EIA report for a read on heating-oil tightness heading into November, with domestic diesel policy a key swing factor.

Watch items

The next OPEC+ ministerial communiqué, EIA's weekly petroleum status report, and any formal US notice on diesel licensing will set the tape. Track Strait of Hormuz shipping data — the first retendered tanker from the Persian Gulf will signal whether Tehran is willing to soften its terms.