The Iranian military announced on Saturday that it was reimposing "strict controls" on the Strait of Hormuz, citing the United States' continued blockade of Iranian ports, less than 24 hours after the key global shipping lane was reopened.

Iran said the strait would remain under strict military control until the US lifted its blockade on Iranian ports, describing the blockade as "piracy and maritime plunder". US President Donald Trump said he does not accept Iran's "blackmail" and that negotiations are "progressing smoothly".

Iranian forces opened fire on a tanker attempting to cross the strait Saturday morning, the Washington Post reported. A container ship was struck by unknown munitions in the strait, with some containers damaged but no casualties reported, according to the UK Maritime Trade Operations (UKMTO) Centre. Two Indian-flagged supertankers were also fired upon by the Revolutionary Guard and turned away.

Trump convened a high-level meeting in the White House Situation Room with senior officials including Vice-President JD Vance, Secretary of State Marco Rubio, Defense Secretary Pete Hegseth and Treasury Secretary Scott Bessent, to discuss the renewed crisis.

Trump said he would know by the end of Saturday whether a deal would be reached. However, as of 8 pm Eastern Time, no progress on the negotiations had been reported. Iranian state media said the Supreme National Security Council is reviewing new proposals put forward by the US. Trump told reporters that Iran “got a little cute” by reimposing controls on the strait, but insisted the US is having “very good conversations” with Tehran.

Shipping data showed several vessels making U-turns in the region on Saturday afternoon, while oil prices edged higher amid uncertainty.

The Strait of Hormuz carries about 20 percent of the global oil trade. It has remained a flashpoint since the US-Israeli strikes on Iran began on Feb 28. Iran has confirmed that more than 3,300 of its citizens have been killed in the conflict, with satellite images showing fires still burning at damaged refineries and crude oil leaking into the Persian Gulf.

Iranian Foreign Ministry spokesman Esmaeil Baghaei said war reparations would be a “top issue” in any negotiations with the US. Iran also announced that six airports, including Tehran’s Imam Khomeini International Airport, have reopened, though no flights have been authorized yet.

The latest incidents further complicate talks aimed at securing a peace deal. A 10-day ceasefire between Israel and Lebanon took effect on Friday, but renewed tensions in the Strait of Hormuz risk undermining that fragile progress.