U.S. President Donald Trump responded on Monday night, making new demands, saying he was seeking his own reparations from Tehran, seemingly leaving the two sides deadlocked.
"We're going to ask for money for the damage they've done over a 50-year period," Trump said at the White House, saying payments would cover deaths among both civilian demonstrators and U.S. forces in the region.
"So if there's damages to be paid, I think Iran should pay those damages," Trump said.
Despite tentative signs of progress in diplomacy, there were reports of new attacks on shipping in the Gulf of Oman and the Red Sea, highlighting the widening threat to maritime trade.
Four crew members were killed in a suspected attack by Yemen's Iran-backed Houthis on a small cargo vessel in the Bab el-Mandeb strait on Tuesday, Yemen's Transport Ministry said.
The fatalities aboard the Egyptian-owned Tihamah, if confirmed, would be the first deaths in a Houthi strike on shipping since the Iran war began. The Houthis have not claimed the attack.
A container ship was also hit by a missile off Pakistan, while sailing through the Gulf of Oman in a suspected U.S. attack, sources said.
The Wall Street Journal reported a U.S. official as saying that the ship had been hit by a U.S. military helicopter after its crew ignored warnings from personnel working to enforce a naval blockade on Iranian ports.
The U.S. first announced a blockade of shipping trying to reach Iran's ports in April and reimposed it in July after the June peace accord crumbled.
The Houthis declared a maritime embargo against Saudi Arabia in the Red Sea on July 20 in response to what they described as a Saudi siege. Riyadh denies that Yemen is under siege.
Trump is under pressure to end a war that U.S. polls show is deeply unpopular with the U.S. electorate, just months before key midterm elections in which his Republican Party risks steep losses with high gasoline prices a key pain point.
So far, a months-long U.S. military campaign, including a two-week campaign of strikes in July, has not broken Iran's grip on the strait, despite Trump saying the strait was open and that the "only one that has control of the Strait of Hormuz right now is the United States Navy."