Global oil prices climbed sharply and stock markets slipped after additional attacks on cargo vessels in the Gulf heightened fears about energy supply disruptions.

Benchmark Brent crude briefly rose more than 9% on Thursday, pushing prices back above $100 per barrel before easing slightly to about $97.90 later in the session.

The surge came despite an announcement by the International Energy Agency (IEA) that it would release a record 400 million barrels of oil from strategic reserves in an effort to stabilise markets and limit the economic fallout from the conflict involving the United States, Israel and Iran.

Market anxiety intensified after reports that three more cargo vessels had been struck in the region, adding to concerns that shipping routes critical to global energy supplies could remain under threat.

Investors fear the global economic recovery could be delayed if attacks on shipping and energy infrastructure continue around the Strait of Hormuz, one of the world’s most important maritime routes for oil and gas.

The narrow waterway serves as a major transit corridor for crude oil shipments and liquefied natural gas exports. Refineries in surrounding countries also produce large quantities of jet fuel and diesel that are distributed worldwide.

Because of security concerns, the strait is now effectively closed to many vessels as shipping companies weigh the risks of operating in the area.

A spokesperson for the Islamic Revolutionary Guard Corps warned that ships linked to the United States, Israel or their allies could be targeted.

“You will not be able to artificially lower the price of oil. Expect oil at $200 per barrel,” the spokesperson said.

“The price of oil depends on regional security, and you are the main source of insecurity in the region.”

Global stock markets reacted negatively to the escalating situation. In Europe, the FTSE 100 in London fell by 0.6% in early trading, while Germany’s DAX, France’s CAC 40 and Spain’s IBEX 35 also declined.

In Asia, Japan’s Nikkei 225 ended the day about 1% lower.

The IEA said the conflict in the Middle East is “creating the largest supply disruption in the history of the global oil market”.

According to the agency, several major producers — including Iraq, Qatar, Kuwait, the United Arab Emirates and Saudi Arabia — have collectively reduced oil output by at least 10 million barrels per day.

The IEA warned that restoring production could take weeks or even months depending on how quickly workers, equipment and other resources can safely return to affected energy facilities.

All 32 member countries of the agency have agreed to the unprecedented release of oil reserves in a coordinated effort to ease supply shortages and bring down rising prices.

The Supreme Court of the United States has struck down some of the most expansive global tariffs introduced by Donald Trump, reshaping the legal landscape around executive authority in trade policy and creating fresh uncertainty in international markets.

In a 6–3 decision, the court ruled that the legal basis used by the administration to impose sweeping tariffs did not grant the president authority to do so. The judgment paves the way for potentially billions of dollars in refunds to businesses and states that challenged the measures.

At the centre of the case was the administration’s reliance on the International Emergency Economic Powers Act (IEEPA), a statute that allows the president to regulate economic activity during national emergencies. The White House argued the tariffs were justified under this authority as part of efforts to address drug trafficking and trade imbalances.

However, challengers contended that while the law permits regulation, it makes no explicit provision for imposing tariffs — a power traditionally reserved for Congress.

Writing for the majority, Chief Justice John Roberts emphasised that when Congress delegates tariff powers, it does so clearly and with defined limits.

The ruling affects duties introduced last year on imports from numerous countries, initially targeting partners such as Mexico, Canada, and China before expanding significantly during the administration’s “Liberation Day” policy push in April.

Supporters of the tariffs had argued they would stimulate domestic investment and revitalise US manufacturing. Critics, however, warned of higher import costs and broader economic ripple effects.

The case was widely viewed as a defining test of executive reach in trade matters — and of the judiciary’s readiness to scrutinise policy initiatives central to the administration’s agenda.

With the decision now issued, the balance between presidential emergency powers and congressional authority over taxation and trade has been more sharply defined, setting an important precedent for future administrations.

Inflation in the United States eased in January, helped by falling costs for energy and used vehicles, offering encouraging signs for economic stability.

New data from the Labor Department showed the Consumer Price Index rose by 2.4% over the 12 months to January — down from 2.7% the previous month and marking the slowest pace of price growth since May.

The moderation in inflation is likely to strengthen arguments from President Donald Trump and others that the Federal Reserve may be able to reduce interest rates without reigniting price pressures.

While the latest figures point to steady progress toward the Fed’s 2% inflation target, analysts caution that the path ahead may not be entirely smooth. Some warn that inflation could stabilise or even edge higher if businesses begin passing on tariff-related costs to consumers, or if labour shortages push up service prices.

For now, however, there are few indications that tariffs are having a broad impact. Core commodity prices — excluding food and energy — remained largely unchanged during the month, suggesting underlying price pressures are contained.

Neil Birrell, chief investment officer at Premier Miton Investors, noted that while the longer-term effects of tariffs remain uncertain, January’s data may contain statistical quirks that influenced the outcome.

Even so, he said the report is likely to “ease the path towards a cut in rates sooner rather than later”.

“The US economy looks to be in fine fettle with growth strong, inflation stable, the job market looking firmer and a Fed that has room to manoeuvre,” he added.