The Strait of Hormuz, a chokepoint for about a fifth of the world’s oil, has again become the chaotic centre of the United States-Israel war on Iran, as a standoff between Washington and Tehran is complicating efforts to end the war.

Iran on Saturday reversed its decision on reopening the strait, and its military opened fire at a ship trying to pass through the waterway after US President Donald Trump said Washington will continue its blockade on Iranian ports.

Trump has refused to end the blockade until a deal is finalised. On Saturday, he said that there have been “very good” discussions, but Washington won’t be “blackmailed”.

After a short-lived rise in transit attempts on Saturday, ships in the Persian Gulf once again stayed put, after reports of vessels coming under fire mid-passage and being forced to withdraw.

Their pullback restored the strait to its pre-ceasefire status, raising the risk of a worsening global energy crunch and increasing the likelihood of renewed fighting.

Here is what you need to know:

What has Iran said?

Iranian Foreign Minister Abbas Araghchi on Friday said the strait would be open for commercial vessels during the truce, which ends on April 22, in “line with the ceasefire in Lebanon”.

However, Iran’s Islamic Revolutionary Guard Corps (IRGC) announced a clear reversal in Iran’s position, saying the Strait of Hormuz would not return to its “previous state”, amid the blockade of Iranian ports.

The IRGC’s joint military command said the US has “continued acts of piracy and maritime theft under the guise of a so-called blockade”.

“For this reason, control of the Strait of Hormuz has returned to its previous state, and this strategic waterway is now under strict management and control by the armed forces,” said the statement, cited by Iranian broadcaster IRIB.

“Until the United States restores full freedom of navigation for vessels travelling from Iran to their destinations and back, the status of the Strait of Hormuz will remain tightly controlled and in its previous condition,” it added.

Iran’s Speaker of Parliament Mohammad Bagher Ghalibaf, who is Iran’s chief negotiator in talks with the US, said it was “impossible for others to pass” the strategic strait without Iran’s consent. He called Washington’s blockade “ignorant” and “foolish”, saying Tehran would not allow others to transit the strait if its own ships were blocked.

On Saturday, he said that major differences remain, despite some progress towards a deal.

What has the US said?

In a Truth Social post on Sunday, the US president ‌accused Iran of violating the ceasefire agreement, but added that US negotiators will be heading to Islamabad, Pakistan on Monday to strike a deal.

“We’re offering a very fair and reasonable deal, and I hope they take it because, if they don’t, the United States is going to knock out every single power plant, and every single bridge, in Iran,” he said in the post.

Iran on Sunday said that it was tightening its control over the waterway once again in response to the US blockade of Iranian ports, which began on April 14. Tehran says the blockade violates the terms of the ceasefire.

Trump on Saturday said that the US was having “very good conversations” with Iran, but he noted that Tehran wanted to close the important oil corridor again and that it could not blackmail the US with such a move.

What is happening in the strait right now?

Lloyd’s List, a maritime firm, said traffic in the Straight of Hormuz had come to a halt after Iranian forces fired on several ships on Saturday.

The United ⁠⁠Kingdom ⁠⁠Maritime Trade Operations agency said it received a report ⁠⁠of a tanker being fired upon by what it ‌‌said were two gunboats linked to the IRGC.

Meanwhile, India summoned the Iranian ambassador in New Delhi and expressed deep concern that two Indian-flagged ships had come under fire in the strait, the government said.

Abas Aslani, a senior fellow at the Centre for Middle East Strategic Studies in Tehran, said the two sides are “engaging in war rhetoric ahead of any possible escalation and military conflict”.

“It seems that they are pressuring each other to win concessions – and we are not there yet,” Aslani told Al Jazeera.

“There are speculations that maybe the US is possibly planning to engage in limited strikes against Iran, but Iran has been saying that it will retaliate strongly,” he said. “This might end again in a wider conflict.”

What are other sticking points between the US and Iran?

Nuclear enrichment

The biggest contention is over hardening positions on Iran’s nuclear programme, chief among them being Tehran’s nuclear enrichment capability.

On Friday, Trump said Washington would obtain Iran’s enriched uranium, calling it “nuclear dust” and referring to the 440kg (970lbs) believed to be buried at sites hit by US strikes last year. He repeated on Truth Social that “the USA will get all Nuclear ‘Dust’”.

Speaking to Reuters news agency, Trump said the US would work with Iran “at a nice leisurely pace” and “start excavating with big machinery” to recover the material.

In a rebuke to Trump, Iran’s President Masoud Pezeshkian said Washington had no justification for depriving Iran of its nuclear rights.

“Trump says Iran cannot make use of its nuclear rights, but doesn’t say for what crime. Who is he to deprive a nation of its rights?” Pezeshkian asked, according to the Iranian Students’ News Agency.

Israel and the US have repeatedly accused Iran of enriching uranium to develop nuclear weapons. But Iran says its nuclear programme is for civilian purposes and that it has honoured its commitments under the Nuclear Non-Proliferation Treaty.

Tulsi Gabbard, the director of US National Intelligence, testified to Congress in March 2025 that the US “continues to assess that Iran is not building a nuclear weapon and Supreme Leader [Ayatollah Ali] Khamenei has not authorised the nuclear weapons programme he suspended in 2003.”

Khamenei was killed on February 28 in US and Israeli strikes. His son Mojtaba Khamenei has been named his successor.

Lebanon

A ceasefire in Lebanon had also been a key Iranian demand before it agreed to the two-week truce between the US-Israeli side and Iran.

While a 10-day ceasefire is technically in place between Israel and the Lebanese armed group Hezbollah, it remains fragile. Israel has carried out strikes despite the truce, and its forces have created a Gaza-like “yellow line” to create a buffer zone.

The truce was declared just days after Lebanon and Israel held their first face-to-face negotiations in decades in Washington. According to Iran’s FM Araghchi, the brief reopening of the Strait of Hormuz came in response to the ceasefire being extended to Lebanon.

Hezbollah has condemned the ceasefire agreement as “an insult to our country” and “a slippery slope with no end in sight”.

“A ceasefire means a complete cessation of all hostilities”, the Lebanon-based group said. “Because we do not trust this enemy, the resistance fighters will remain in the field, ready to respond to any violations of the aggression. A ceasefire cannot be unilateral; it must be mutual”.

Hezbollah is Tehran’s most powerful regional ally and a core pillar of the “axis of resistance” – a network of armed groups across the Middle East aligned with Iran against Israel, including Yemen’s Houthis and several factions in Iraq.

The group joined the fighting after the Israeli army killed Iran’s Supreme Leader Khamenei in its initial strikes on Tehran.