Iran has accused the United States of derailing talks in Islamabad after the two sides had come close to reaching an agreement.
"We engaged with the US in good faith to end the war," Iranian Foreign Minister Abbas Araghchi has said in a statement.
He said the parties had been "just inches away" from an "Islamabad MoU" (memorandum of understanding) before encountering "maximalism, shifting goalposts and a blockade" from the US side.
"Good will beget(s) good will. Enmity begets enmity," Araghchi added.
Talks collapse
The remarks have come shortly after US Central Command (CENTCOM) announced that it would begin enforcing a blockade on all maritime traffic entering and leaving Iranian ports starting Monday.
The blockade excludes vessels transiting the Strait of Hormuz to and from non-Iranian ports.
The development has followed the latest round of Iranian-US talks in Islamabad, which ended without an agreement.
The negotiations on Saturday, mediated by Pakistan, ended following multiple rounds of discussions and exchanges of proposals but failed to produce a breakthrough.
The two sides left Islamabad with key differences unresolved, with both signalling that further diplomatic efforts would be needed.
The talks were part of broader efforts to end the US-Israeli war on Iran that began on February 28, under a fragile two-week ceasefire brokered earlier.
