Disruptions in and around the Strait of Hormuz threaten to further slow international shipments after US-Iran talks failed and Washington imposed a blockade on traffic entering or leaving Iranian ports, shipping experts said.

The US military's blockade of ships "entering or departing Iranian ports and coastal areas" in the Strait of Hormuz located between Iran and Oman took effect on Monday. The Strait links the Gulf north of it with the Gulf of Oman to the south and the Arabian Sea beyond.

No vessels have made it past US naval forces during the first 48 hours of the blockade, according to US Central Command. Even so, US President Donald Trump said the war in Iran was "very close to over" in an interview that aired on Wednesday, The Associated Press reported.

The AP reported that the commander of Iran's joint military command on Wednesday threatened to halt trade in the Gulf region if the US does not lift its blockade on Iranian ports.

At least 15 US warships formed the blockade of Iranian ports, according to the UK Maritime Trade Operations, part of the UK Royal Navy.

International Maritime Organization Secretary-General Arsenio Dominguez said 20,000 seafarers and approximately 1,600 vessels were stuck in the Gulf on Monday evening.

The disruption is a major concern for shipping firms, businesses and oil traders.

The price for a barrel of Brent crude, the international standard, added 0.1 percent to settle at $94.93 on Wednesday, still well above its roughly $70 price before the war.

"The Strait of Hormuz [carries] approximately 20 million barrels of oil, which is 20 percent of the world's daily oil supply and one-third of seaborne oil supply that passes through this narrow waterway that is basically controlled by Iran," Mohammad N. Elahee, a professor of international business at Quinnipiac University in Connecticut, told China Daily.

Iran exported 1.84 million barrels per day of crude oil in March. In April, it has so far shipped 1.71 million barrels per day, compared to an average of 1.68 million barrels per day in 2025, maritime data firm Kpler reported.

Trump has repeatedly pressed for free passage for global shipping through the Strait.

He posted on Truth Social on Monday that 34 ships had passed through Sunday. Kpler reported it was just 14.

Iran has been allowing a small number of ships to go through the shipping channel since the war began on Feb. 28.

It wants ships to coordinate with its forces and pay a toll.

Two Iran-linked vessels got through on Monday, before the US blockade, Kpler said.

Yet, it's far fewer than the 130 daily crossings before the US-Israel war on Iran began.

Trump once floated the idea that the US Navy could escort ships through the Strait.

"That would be very hard," Robert Kaufmann, an affiliate faculty member at Boston University Global Development Policy Center and an expert on the world's oil markets, told China Daily. "The US Navy could in theory escort ships through there, but that would be expensive and slow."

German shipping giant Hapag-Lloyd told The Washington Post its vessels would not be sailing through the Strait over safety concerns.

Ships will be forced to find longer shipping paths, raising the cost of fuel, say experts.

Iran is adamant it plans to retain effective control of the Strait and dubbed the US blockade "piracy".

Trump warned that any Iranian "fast-attack" ships that go near the US blockade would be "eliminated".

Several US allies in Europe refused to join the US blockade.

French President Emmanuel Macron and Britain will co-host a virtual meeting this week to forge an international coalition that guarantees passage for ships in the Strait.

United Nations spokesperson Stephane Dujarric urged all sides to ensure freedom of navigation through the Strait.

"The secretary-general's position has been consistent: No one should do anything that harms the freedom of navigation in the Strait of Hormuz," Dujarric said in a statement. "That freedom of navigation is based on international law and years and years of custom."

The Strait is also a key global transportation route for fertilizer, meaning delays and disruptions will likely affect farmers.

"The cost of fertilizer has increased," Luis A. Ribera, professor and extension economist in the Department of Agricultural Economics at Texas A&M University, told China Daily. "Slower shipments through the Strait of Hormuz makes fertilizer prices increase more, both because of the slower shipments but also because of the uncertainty."

The UN Food and Agriculture Organization warned that the crisis could lead to higher food prices globally.

William W. Wilson, a professor in agribusiness and applied economics at North Dakota State University, told China Daily: "Everything going on in Hormuz is very negative to agriculture — negative for the world economy and for the world food economy in particular."