The Iranian delegation led by chief negotiator Mohammad Bagher Ghalibaf has departed for Tehran, ending a marathon 18-hour session of talks with US counterparts in Switzerland.
State media reported that the group left the negotiation venue Monday morning without announcing any breakthrough, marking a sharp contrast to the optimistic tone of recent diplomatic exchanges.
The departure comes at a critical juncture for global energy markets, which have been pricing in a sustained thaw in US-Iran relations.
Just days ago, Iranian Foreign Minister Abbas Araghchi announced that restrictions on Iranian oil exports had been lifted, a move that significantly reduced geopolitical risk premiums in crude benchmarks.
The sudden halt in negotiations raises questions about whether that de-escalation is reversible or if technical disagreements have stalled the broader agreement.
Markets are likely to reassess the probability of a near-term supply surge from Iran.