Tehran accused the United States of "excessive demands,” Iranian media said on Saturday, as US media reports raised the prospect that Washington was mulling new strikes and Iranian leaders considered the latest peace proposal.
Pakistan's powerful army chief arrived in Tehran on Friday to bolster mediation and US President Donald Trump abruptly changed his plans to skip his son's wedding to stay in Washington due to "circumstances pertaining to government,” fueling speculation that the situation had entered a sensitive stage.
Trump has described the stop-start negotiations this week as teetering on the "borderline" between renewed attacks and a deal to end the war, which began with US-Israeli strikes on Iran on February 28 and led to competing blockades around the strategic Strait of Hormuz that have roiled the global economy.
Weeks of negotiations since an April 8 ceasefire -- including historic face-to-face talks hosted by Islamabad -- have still not produced a permanent resolution or restored full access to the strait, choking vast quantities of global oil supply.
Iran's Foreign Minister Abbas Araghchi said in a call with UN Secretary-General Antonio Guterres that Tehran was engaged in the diplomatic process despite "repeated betrayals of diplomacy and military aggression against Iran, along with contradictory positions and repeated excessive demands" by the United States, according to the ministry.
US media outlets Axios and CBS News, citing unnamed sources, reported the White House was considering strikes on Iran, although both added a final decision had not been made yet.
US officials have repeatedly raised the prospect of renewed action against Iran if a deal were not reached, with Secretary of State Marco Rubio saying on the sidelines of a NATO conference in Sweden that there had been "some progress" towards a peaceful resolution but "things were not there yet.”
"We're dealing with a very difficult group of people. And if it doesn't change, then the president's been clear he has other options," he said.
Pakistan's army chief Asim Munir landed in Tehran on Friday where he met with Araghchi late into the night to discuss "the latest diplomatic efforts and initiatives aimed at preventing further escalation,” according to the official IRNA news agency.
Iranian foreign ministry spokesman Esmaeil Baqaei cautioned that the visit did not mean "we have reached a turning point or a decisive situation" with "deep and extensive" disagreements remaining, according to Iran's ISNA news agency.
AFP quoted Baqaei as saying that a delegation from Qatar had also held talks with the Iranian foreign minister on Friday.
"In recent days, many countries -- both regional and non-regional -- have been trying to help bring the war to an end ... However, Pakistan remains the official mediator," he said.
Pakistan's Prime Minister Shehbaz Sharif and Foreign Minister Ishaq Dar -- who have played a crucial role in mediation between the warring sides -- flew to China, Iran's top trading partner, for a four-day visit in which efforts to resolve the Middle East crisis were expected to be discussed.
Baqaei said the status of the Strait of Hormuz and a retaliatory US blockade of Iranian ports were also under discussion.
The future of the strategic maritime chokepoint remains a key sticking point, with fears growing that the global economy will suffer as pre-war oil stockpiles run down.
