As the war neared six months old, the two sides were not exchanging fire but also not pursuing peace talks.
All the while, oil shipments through the Strait of Hormuz have virtually halted as Tehran clings to its leverage by threatening to strike any unauthorised oil tankers that attempt to transit the narrow waterway.
US Treasury Secretary Scott Bessent will hold a media conference on Monday amid promises to reveal "the toughest sanctions in history" on Iran while also urging China to co-operate with Washington.
China buys more than 80 per cent of Iran's shipped oil, according to 2025 data from analytics firm Kpler.
Beijing urged diplomacy.
Iranian foreign ministry spokesman Esmaeil Baghaei said on Saturday that the imminent US announcement of new economic sanctions on Iran was an "assertion of extraterritorial sovereignty over every independent member state of the United Nations".
"Such secondary sanctions find no foundation in international law," he said in a post on X.
US President Donald Trump, who has warned of economic consequences against any country that provides "any type of lifeline to Iran", said on Friday that Washington was observing "what happens" in the conflict.
"They would love to make a deal, but they're not ready to make the right deal, in my opinion," Trump said of Iran.
While the US has effectively blockaded Iranian vessels in their ports, the Strait of Hormuz remained bottled up with thousands of seafarers stranded on hundreds of vessels.
Only four commodity ships sailed along the strait on Thursday, none of them large crude carriers or liquefied natural gas tankers, ship-tracking data showed.
However, Iran has granted permission for a number of Iraqi oil tankers to pass through the Strait following repeated requests from Baghdad, Iran's state news agency IRNA reported on Saturday.
IRNA said obtaining special permission for Iraqi tankers was one of Baghdad's main requests during Iranian parliament speaker Mohammad Baqer Qalibaf's visit to Iraq.
US Energy Secretary Chris Wright said the US military helped move a seven-day average of eight million barrels a day of oil through the strait.
That is down from more than 20 million per day before the war or about one of every five barrels consumed worldwide.
US attacks have severely diminished Iran's economy and devastated its navy and air force, but Tehran maintains enough missile and drone capability to impede oil tanker traffic and attack regional rivals.
Trump, meanwhile, has yet to achieve objectives he set at the start of the war such as dismantling Iran's nuclear program - the state of which remains uncertain given that UN inspectors have been shut out since 2025 - and creating conditions for Iranians to overthrow their clerical rulers.
Thousands have been killed, including 168 Iranian schoolchildren on the first day of the war.
The US has reported more than 750 military personnel wounded and 18 killed.
The chief of staff of Iran's armed forces, Major General Ali Abdollahi, promised on Friday that Iran would respond to enemy threats militarily with "crushing, punishing and devastating responses".
Still, President Masoud Pezeshkian called for a diplomatic solution.
"It would be better to end the war today, when we are powerful and have dignity, and the whole world acknowledges our victory and emphasises that America, contrary to all regulations, attacked our schools, hospitals, and infrastructure and is hated in the world," Pezeshkian said, according to the ISNA news agency.
