US–Iran ceasefire strained as shipping clash and diplomatic confusion cloud planned talks

JUST days before a ceasefire between the United States and Iran is due to expire, tensions have escalated sharply amid conflicting accounts over planned talks and renewed incidents at sea.

US President Donald Trump said on Sunday that American officials would attend a second round of negotiations in Islamabad this week. However, Iranian state media swiftly contradicted that claim, reporting that no such meeting had yet been agreed.

The New York Times reported that the dispute unfolded alongside a potentially destabilising development in the Strait of Hormuz, where Trump said a US Navy destroyer had attacked an Iranian cargo vessel accused of breaching a US-imposed blockade. The strike, if confirmed, risks undermining the already fragile ceasefire.

Hours after Washington signalled its readiness for talks, Iran’s state news agency IRNA reported that negotiations remained stalled, citing what it described as “excessive” and “unreasonable” US demands.

The agency added that the ongoing blockade of Iranian ports “have so far hindered progress in the negotiations”.

A White House official said J.D. Vance was expected to lead the American delegation, accompanied by senior advisers Steve Witkoff and Jared Kushner. If convened, the meeting would follow an initial round of high-level talks held after a two-week ceasefire came into effect on April 8.

Maritime tensions have compounded the diplomatic uncertainty. Trump accused Iran of firing on vessels transiting the strait “in a total violation of our ceasefire agreement”, despite a prior announcement on April 17 that the waterway had been reopened.

The United States, however, maintained its naval blockade on Iranian shipping, a move that angered Tehran and prompted it to again declare the strait closed.

Iranian spokesperson for the Ministry of Foreign Affairs Esmaeil Baqaei said the blockade constituted a breach of the ceasefire and an unlawful act amounting to a “war crime and crime against humanity” because it was “deliberately inflicting collective punishment” on the Iranian people.

Independent monitoring added to concerns over maritime safety.

The United Kingdom Maritime Trade Operations reported that Iranian Revolutionary Guard gunboats fired without warning on a tanker on April 18, while a separate container ship was “hit by an unknown projectile”.

Both vessels were Indian-flagged, prompting a diplomatic protest from New Delhi. Several ships have since reversed course, though no further incidents were reported by the evening of April 19.

Iranian media also reported that at least two tankers were forced to change course by Iranian forces while attempting to transit the strait.

Against this backdrop, Trump issued a stark warning tied to the outcome of any negotiations. “We’re offering a very fair and reasonable DEAL,” he wrote on social media. “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.”

Such threats have drawn scrutiny under international law, where attacks on civilian infrastructure are generally prohibited. Mike Waltz defended the position, arguing that dual-use infrastructure could be considered legitimate targets.

“We have a long history of taking down bridges, power plants and other infrastructure that is powering Iran’s military,” he said. “In the laws of land warfare and the rules of engagement, any type of infrastructure that is commingled is absolutely a legitimate target.”

The previous round of talks in Islamabad ended without a breakthrough, despite being the highest-level engagement between the two sides in decades.

Trump has since claimed that Iran had agreed to most US demands regarding its nuclear programme, a claim Iranian officials have firmly rejected.

Pakistan has not formally confirmed it will host another round of talks, though security measures in Islamabad have intensified, mirroring those seen during the earlier negotiations.

Reports indicate a lockdown in parts of the city, the evacuation of a luxury hotel used for prior meetings, and the planned deployment of thousands of additional security personnel.

The uncertainty surrounding both the negotiations and maritime security has dimmed what had briefly appeared to be a moment of cautious optimism in the region.

A separate ceasefire in Lebanon, agreed under US pressure between Israel and the Iran-backed group Hezbollah, had been seen as a potential stepping stone towards broader de-escalation. - April 20, 2026