Just before US President Donald Trump’s deadline for reopening the Strait of Hormuz was set to expire, Iran reportedly cut off every formal and backchannel route of contact with Washington.

According to Iran’s Tehran Times, authorities in Tehran have stopped both direct diplomatic engagement and indirect message exchanges with the United States, effectively freezing communication at a critical moment in the standoff.

The development unfolded as Trump intensified his rhetoric on Truth Social, describing the coming hours as potentially historic. In a stark warning, he suggested catastrophic consequences could follow if the situation did not change, framing the moment as decisive in ending decades of what he characterised as turmoil and hostility linked to Iran.

Despite the heightened language from the White House, signals earlier in the day pointed to ongoing engagement. US Vice President JD Vance indicated that negotiations were still in progress and voiced hope that discussions before the cutoff could yield a constructive outcome.

Separately, an unnamed American official told Fox News that communication lines with Tehran had not entirely broken down and described the dialogue as encouraging, expressing optimism about a possible resolution before the end of the day.

International players have also reportedly been involved in facilitating dialogue. Media outlets including CNN and Al Jazeera reported that Pakistan has been working behind the scenes to help sustain contact between the two sides. A Pakistani security source told CNN that both civilian and military leadership were pushing for progress in order to prevent further escalation.

The Strait of Hormuz remains central to the crisis, given its strategic importance to global energy shipments, and uncertainty continues to loom as the deadline approaches.