TEHRAN – Iran and the United States appeared to avoid an impasse on Sunday as they wrapped up a fourth round of indirect nuclear talks, which has been characterized as the most difficult round of discussions so far.

Iran’s Foreign Ministry Spokesman Esmaeil Baqaei, part of Iran’s negotiating team in Oman alongside technical, legal, and nuclear experts, said the talks were difficult, but were also “useful”. He said the discussions helped the two sides “understand each other’s positions” and “find reasonable and realistic ways to address the differences.”

Tehran and Washington agreed to hold a fifth round of negotiations, with the timing and location to be announced by the mediator, Oman. The Arab state has been coordinating the discussions and also acting as a go-between.

The relative success of the latest round comes as observers had expected a potential collapse in the diplomatic process, after Washington’s lead negotiator, special presidential envoy Steve Witkoff, said during an interview earlier in the week that the U.S. wants concessions on Iran’s redlines or it will withdraw from the talks.

It appears that Witkoff avoided raising the demands he referenced in the interview—the dismantling of Iran’s nuclear facilities and an end to uranium enrichment—since Tehran had previously stated it would never accept such conditions. The Tehran Times understands that Iran’s stance remains unchanged, and the agreement to hold a new round of talks indicates the U.S. continues to acknowledge that position.

Witkoff’s remarks, however, were condemned by Iran’s Foreign Minister Seyyed Abbas Araghchi on Sunday.  “If the U.S.’ contradictory stances are repeated, Iran will have to act accordingly,” he told Iran’s national television after stating that such moves not useful in any shape or form. The top diplomat has been leading his country’s negotiating team in the indirect talks with Washington.

Araghchi added that the two sides now understand each other better.  “Compared to the previous three rounds, this session was much more direct and serious. We moved away from generalities and focused on details, which naturally made the negotiations more difficult.”

This is the second time in the past two decades that Iran is negotiating a deal on its nuclear program. It signed one named the Joint Comprehensive Plan of Action (JCPOA) in 2015, after two years of intense discussions with the U.S., UK, France, Germany, China, and Russia. The deal limited Tehran’s nuclear activities in exchange for the removal of sanctions.

U.S. President Donald Trump, however, threw the JCPOA into disarray during his first term in office, after he unilaterally left the pact and re-instated sanctions against Iran. He was hoping to also ensure caps on Tehran’s military capabilities and foreign policy, demands he now seems to understand are non-starters.

Araghchi and other Iranian officials are still not fully counting on what they hear from the American side at the negotiating table, the Tehran Times has learned. Beyond Washington’s own fickleness, attempts by other actors to sabotage the talks have further fuelled doubts about the feasibility of a deal. Among these disruptive forces are Israel—which has pushed for U.S. military action against Iran—Europe, frustrated over its exclusion from the negotiations, and American Democrats who previously supported the JCPOA.