Foreign Minister Abbas Araqchi announced on social media that the strait, a slender chokepoint in global energy trade, was open for all commercial vessels for the remainder of the United States-brokered 10-day truce that was agreed on Thursday between Israel and Lebanon, which was invaded by Israel after the Iran-allied Hezbollah militant group joined the fighting.
US President Donald Trump, who with Israel launched the war on Iran on February 28 this year that has killed thousands of people and led to the strait's de facto closure, told supporters at a rally in Arizona that Araqchi's announcement marked "a great and brilliant day for the world."
But subsequent statements and clarifications from both sides left uncertainty over how quickly shipping might return to normal, and some vessels could be observed making unsuccessful attempts cross the strait on Friday before turning back.
Trump said a US blockade of ships sailing to Iranian ports, announced after talks with Iran last weekend ended without agreement, would remain until "our transaction with Iran is 100% complete".
Iran responded sharply, with Iran's parliament speaker and senior negotiator Mohammad Baqer Qalibaf saying in a social media post that the strait, which until recently carried about a fifth of the world's oil trade, "will not remain open" if the US blockade continues.
He also said Trump had made multiple false claims about the peace talks on Friday.
About a fifth of the world's oil and liquefied natural gas supplies normally pass through the strait, which is the only sea exit for the fuels from key exporting countries.
OPEC members Saudi Arabia, Iran, the United Arab Emirates, Kuwait and Iraq export most of their crude via the waterway. Qatar, among the world's biggest liquefied natural gas exporters, sends almost all of its LNG through the strait, while analytics firm Kpler estimates about 33% of the world’s fertilisers, including sulphur and ammonia, pass via the strait.
Iran has said all ships must coordinate with the Islamic Revolutionary Guard Corps, which was not the case before the war. The Defense Ministry said in a statement quoted by state television that military vessels and ships linked to "hostile forces", US and Israel, were still not permitted to pass.
Vessel traffic data showed a group of about 20 ships, including container ships, bulk carriers, and tankers, moving through the Gulf toward the Strait of Hormuz on Friday evening, but most ended up turning back, although it was not clear why. The group included three container ships operated by French shipping group, which declined to comment.
It was the largest group of vessels to attempt the transit since the start of the war.
It also was unclear how the two sides would address Iran's nuclear programme, which has been a key sticking point in peace talks so far, with Iran defending its right to what it says is a civilian nuclear energy programme.
Trump told Reuters the US would remove Iran's stockpiles of enriched uranium. Foreign Ministry spokesperson Esmaeil Baghaei told state TV the material would not be transferred anywhere.
Separately, a senior Iranian official said that Iran hoped a preliminary agreement could be reached in the coming days that could extend a ceasefire that is due to expire next week. That could buy more time for negotiations on lifting sanctions on Iran and securing compensation for war damages, the official said.
OIL PRICES TUMBLE, STOCKS JUMP
Oil prices fell about 10%, and global stocks jumped on the news that marine traffic might flow through the strait again.
Shipping companies cautiously welcomed Iran's announcement but said they would require clarifications, including about the risk of mines, before vessels move through the entry point to the Gulf.
The US Navy warned seafarers that the mine threat in parts of the waterway was not fully understood and said they should consider avoiding the area.
A senior Iranian official said ships could pass only under coordination with Iran's Islamic Revolutionary Guard Corps.
After a video conference on Friday, more than a dozen countries said they were willing to join an international mission to protect shipping in the strait when conditions permit, Britain said.
DIPLOMACY PROGRESS
Trump told Reuters there could probably be more talks this weekend. Some diplomats said that was unlikely given the logistics of gathering in the Pakistani capital Islamabad, where the talks are expected to take place.
Troops were deployed along routes into Islamabad on Friday, though roads remained open and the government had not ordered business closures, as it did ahead of the previous meeting.
A Pakistani source involved in mediation efforts said an upcoming meeting could result in an initial memorandum of understanding, followed by a comprehensive deal within 60 days.
"Both sides are agreeing in principle. And technical bits come later," said the source, who spoke on condition of anonymity.
A senior Iranian official told Reuters there had been an agreement on unfreezing billions of dollars in Iranian assets as part of the accord, without giving a timeline.
At last weekend's talks, the US proposed a 20-year suspension of all Iranian nuclear activity, while Iran suggested a halt of three to five years, according to people familiar with the proposals.
Iran has demanded the lifting of international sanctions, while Washington has pressed for any highly enriched uranium to be removed from Iran.
Two Iranian sources have said there were signs of a compromise that could remove part of the stockpile.
Trump told Reuters the US might not act quickly. "We're going to go in with Iran, at a nice leisurely pace, and go down and start excavating with big machinery... We'll bring it back to the United States," he said in a phone interview.
He mentioned "nuclear dust", a reference to the aftermath of bombing strikes by the US and Israel on Iran's nuclear installations in June last year.
Despite Trump's optimism, Iranian sources told Reuters that "gaps remained to be resolved" before a preliminary deal, while senior clerics struck a defiant tone during Friday prayers.
"Our people do not negotiate while being humiliated," cleric Ahmad Khatami said.
The US-backed ceasefire between Israel and Lebanon appeared to be largely holding on Friday, despite Lebanese Army reports of some Israeli violations. Paramedics said an Israeli drone strike killed one person in southern Lebanon.
The conflict was reignited on March 2 when Hezbollah opened fire on Israel in support of Tehran, prompting an Israeli offensive that authorities say has killed nearly 2300 people.
There was no immediate comment from the Israeli military on the reported ceasefire violations.
