The Iranian president's views came in a phone conversation with Pakistan Prime Minister Shehbaz Sharif and after President Donald Trump cancelled a trip by US envoys in another blow to peace prospects.
In reports by the Mehr news agency, linked to the Iranian Revolutionary Guard, President Pezeshkian criticised continued violations and coercive behaviour by the US during both the negotiations and the ceasefire period.
Such measures, he said, together with threatening rhetoric, have heightened doubts regarding the US commitment to the diplomatic process.
Trump said in a social media post that he had called off the planned visit by his special envoy Steve Witkoff and son-in-law Jared Kushner, citing what he said was tremendous confusion within the Iranian leadership.
"Too much time wasted on traveling, too much work! Besides which, there is tremendous infighting and confusion within their "leadership." Nobody knows who is in charge, including them. Also, we have all the cards, they have none! If they want to talk, all they have to do is call!!!" he wrote.
Iranian Foreign Minister Abbas Araqchi earlier left the Pakistani capital without any sign of a breakthrough in talks with Prime Minister Shehbaz Sharif and other senior officials.
Araqchi later described his visit to Pakistan as "very fruitful," adding in a social media post that he had "shared Iran's position concerning (a) workable framework to permanently end the war on Iran.
Iranian media reported that Araqchi had flown to Oman's capital Muscat, saying he will meet with senior officials to "discuss and exchange views on bilateral relations and regional developments".
Tehran has ruled out a new round of direct talks with the United States and an Iranian diplomatic source said Tehran would not accept Washington's "maximalist demands".
Washington and Tehran are at an impasse as Iran has largely closed the Strait of Hormuz, which normally carries one-fifth of global oil and liquefied natural gas shipments, while the US blocks Iran's oil exports.
The conflict, in which a ceasefire is in force, began with US-Israeli air strikes on Iran on February 28. Iran has since carried out strikes against Israel, US bases and Gulf states, and the war has pushed up energy prices to multi-year highs, stoking inflation and darkening global growth prospects.
Araqchi "explained our country's principled positions regarding the latest developments related to the ceasefire and the complete end of the imposed war against Iran", said a statement on the minister's official Telegram account.
Asked about Tehran's reservations over US positions in the talks, an Iranian diplomatic source in Islamabad told Reuters: "Principally, Iranian side will not accept maximalist demands."
White House press secretary Karoline Leavitt had said the US had seen some progress from the Iranian side in recent days and hoped more would come over the weekend, while Vice President JD Vance was ready to travel to Pakistan as well.
Vance led a first round of unsuccessful talks with Iran in Islamabad earlier this month.
The conflict, in which a ceasefire is now in force, began with US-Israeli air strikes on Iran on February 28. Iran has since carried out strikes against Israel, US bases and Gulf states, and the war has pushed up energy prices to multi-year highs, stoking inflation and darkening global growth prospects.
