A Qatari delegation flew to Tehran on Sunday to push for finalization of a framework agreement to end the war between the United States and Iran, even as Iranian officials cast doubt on whether a deal could be signed by day's end and hardline opposition within Iran continued to complicate the timeline, according to multiple reports from Iranian state media, Reuters and CNN.
The mediation team, headed by an adviser to the Qatari Prime Minister and Foreign Minister, Sheikh Mohammed bin Abdulrahman bin Jassim Al Thani, arrived in the Iranian capital to continue talks held the previous week, Iran's semi-official ISNA news agency reported.
The purpose of the visit is reportedly "to go over the latest developments regarding the diplomatic process."
A source with knowledge of the situation told CNN that the Qatari delegation traveled in coordination with the United States to help facilitate the finalization of the agreement.
A separate source told Reuters that Qatari negotiators were flying to Tehran Sunday morning to help conclude the deal.
The visit comes as U.S. and Pakistani leaders have both signaled a framework agreement could be signed as soon as Sunday, potentially bringing an end to nearly four months of hostilities that began when U.S.-Israeli strikes on Iran commenced Feb. 28.
A Pakistan-brokered ceasefire took effect April 8, and negotiations toward a broader settlement have continued since.
U.S. President Donald Trump announced on Truth Social that a peace deal with Iran was scheduled to be signed Sunday, adding that Iran "no longer wants a Nuclear Weapon, nor will they have one, either through purchase, development, or any other form of procurement."
Trump also warned that if no agreement was reached, the U.S. retained "the ultimate alternative, hopefully never to be used again."
It is not the first such declaration.
Trump has claimed approximately 40 times that a deal was on the verge of completion, only to subsequently revert to threatening Iran with new strikes.
Iran's Islamic Revolutionary Guard Corps (IRGC) pushed back directly against Trump's announcement that the agreement would be signed on Sunday, according to CNN.
Iranian officials and the Qatari delegation held consultations in Tehran, Iranian media reported, but no details of those discussions were disclosed.
Iran's Fars News Agency, citing a source close to the negotiating team, reported that Tehran had not yet announced its final decision on the proposed framework agreement.
The source said the political, legal and technical dimensions of the proposals remained under active review at both expert and decision-making levels, with responsible institutions continuing to assess the various aspects of the document.
The U.S. and Iran have also offered differing accounts of the terms of any prospective agreement, including the timing of signing a Memorandum of Understanding (MoU).
Iran presented its own draft of the proposed agreement through Qatari mediators during an earlier Tehran meeting this week, according to a source cited by CNN.
The latest round of diplomacy unfolded against a backdrop of renewed escalation. Recent days have seen the most intense clashes between Iran and the United States since the April ceasefire.