Iran has agreed to allow International Atomic Energy Agency (IAEA) inspectors back into the country, a significant shift in its nuclear posture.
Vance announced the development, framing it as a concrete step forward in ongoing diplomatic engagement between Washington and Tehran.
The agreement marks a reversal of policy adopted after the 2025 war between Iran and Israel, during which Iran initially severed ties with the nuclear watchdog.
The readmission of inspectors is widely viewed as a necessary precondition for any broader resolution to the region's nuclear standoff.
Markets are likely to view the move as a reduction in geopolitical risk, potentially easing pressure on energy prices and regional equities that have been volatile amid fears of renewed conflict.
The development suggests a window of opportunity for further diplomatic progress.