Iran and the United States ended the fourth round of negotiations on a surprisingly optimistic plot, although the two sides were far apart on the central issue of the uranium enrichment program on Iranian soil.

Oman's negotiations in Muscat lasted four hours and were described as positive by the United States. The Iranian Foreign Ministry said, "Negotiation is difficult, but we need to know the positions of both sides in detail."

"We have moved away from the general field to a large extent and have detailed it. In this case, negotiations have become more difficult," said Iran's Foreign Minister Abbas Araghchi.

Speaking before the conversation began, Araghchi said that Iran would not recover concentrated uranium from its "correct" situation under any circumstances. He added that weapons of mass destruction have no place in Iran's security doctrine.

He said one of the difficulties in the negotiations was the conflict between negotiation rooms inside and outside the U.S. speech.

He added: "Iran may limit things like size, scale, level and quantity to establish a period similar to the previous period" - mentioning restrictions on the purity and inventory of Iran's rich uranium under the original nuclear deal signed in 2015.

Further negotiations may take place within a week, Araghchi said. U.S. President Donald Trump resigned from the nuclear deal in 2018, politically needed to show the strict restrictions on Iran by any new deal.

Before the negotiations, there were concerns about a breakdown as the U.S. government gradually attracted a tougher public route. U.S. Special Envoy Steve Witkoff has hinted that the United States will never allow Iran to benefit from peaceful technologies enriched by uranium, saying all its technologies must be removed and destroyed.

Israel is still in the context of negotiations and repeatedly urges Trump to distrust Iran, but to end any ambiguity about Iran's true purpose by the real purpose of the Iran nuclear program, which is through military military destruction.

"Iran State can no longer achieve a rich plan. This is our red line. There is no richness," Witkoff said on Friday.

Araghchi called for a stop to make demands through the media in the United States, saying it made the negotiation process even more complicated.

The difficulty for the United States is that many other countries are allowed to enrich uranium at home, while Israel's nuclear program has not been declared. But the United States believes that Iran's nuclear program is undisclosed and its high level of enrichment records makes the Tehran regime a special situation.