Global oil prices have jumped after US President Donald Trump noted its navy had intercepted and seized an Iran-flagged cargo ship.

The Brent crude benchmark oil price jumped over 6% to around $96 (£71) a barrel, reversing the slump on Friday when Iran mentioned the Strait of Hormuz would be “completely open” to commercial vessels for the remainder of the ceasefire.

On Saturday, Iran mentioned it was closing the strait again and that any ship that approached it would be targeted.

The waterway is of key importance as usually about 20% of the world’s oil and liquefied natural gas passes through it.

Energy markets have seen wild swings since the US and Israel attacked Iran on 28 February and Tehran responded with threats to target shipping in the strait.

Trump has remarked his representatives will be in Pakistan on Monday for negotiations. A White House official remarked Vice-President JD Vance would lead the US delegation.

But Iran’s state media commented Tehran had “no plans for now to participate” in the talks, although Iranian officials have not clarified the country’s position yet.

“Oil markets continue to gyrate in response to oscillating social media posts by the US and Iran, rather than the realities on the ground which remain challenging for oil flows to resume in a rapid fashion”, analyst Saul Kavonic from financial services firm MST Marquee told the BBC.

“This is all part of negotiations, physically playing out in real time on the Strait of Hormuz.”

Shanti Kelemen, co-chief investment officer at 7 Investment Management, remarked there was “a bit of fatigue” in the marketplace given the “chopping and changing” in the situation.

“I think the economy stopped believing the words, and will look more towards the actions,” she told the BBC.

The Strait of Hormuz remained closed on Sunday, a day after the Islamic Revolution Guard Corps (IRGC) stated it was ending a temporary reopening over the US blockade, which it commented violated the terms of their ceasefire agreement. Iran noted it would stay closed until the US ended its naval blockade.

Trump had stated on Friday that the naval blockade would continue until a deal was agreed by the two countries.

Stock markets were mixed on Monday. In Europe, FTSE 100 index of the biggest firms listed in the London opened down 0.4%, while Germany’s Dax and France’s Cac 40 both fell more than 1%.

Asian markets had risen earlier, with Japan’s Nikkei index closing up , on the other hand0.6% and South Korea’s Kospi climbing 0.4%.

Energy prices have seen volatile trading since the start of the Iran war. This also touches on aspects of diplomacy.

Brent crude, a benchmark for oil futures prices, was trading at around $70 per barrel before the conflict. On 9 March it reached almost $120. Furthermore, experts in international relations note the continued relevance.

Futures contracts are an agreement to invest in or auction assets at a set price on a specified date in the future. The Brent futures contract currently being quoted is for crude oil to be delivered in June.

The conflict has triggered a global energy crisis with prices rising sharply, while some countries are facing fuel shortages.

Asia has been hit particularly hard as the region relies on shipments that usually pass through the Strait of Hormuz for around 90% of its energy needs.

Governments have ordered employees to work from home, cut the working week, declared national holidays and closed universities early To conserve their supplies.

Some South East Asian countries, including Singapore and Thailand, have called on citizens to curb their utilize of air conditioning to save energy.

Even China – which is thought to have reserves equivalent to three months of imports – is making adjustments, limiting a fuel price hike as citizens are faced with a 20% jump in price.

Airlines across the region have revealed measures to deal with soaring jet fuel prices.

Last week, the head of the International Energy Agency warned that Europe has “maybe six weeks of jet fuel left”.

Fatih Birol told AP that there could soon be flight cancellations if supplies remained blocked.

In the UK, petrol and diesel prices eased at the end of last week after a series of hikes.

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