US equity-index futures fell and the dollar strengthened Monday after diplomatic efforts toward a second round of peace talks between the United States and Iran appeared to lose momentum. Traders quickly shifted into safer assets as the breakdown raised fresh concerns about geopolitical stability in the Middle East.

The dollar's climb against major currencies reflected a classic risk-off move, with investors pulling back from equities amid uncertainty. Stock futures declined across major indices as market participants weighed the implications of prolonged tensions between the two nations. Energy markets, closely tied to Middle East stability, showed elevated volatility in early trading.

The stalled negotiations represent a setback for efforts to ease regional tensions through diplomatic channels. Markets have been closely watching for any signs of progress, as a successful deal could have significant implications for global trade and energy prices. The reaction in futures suggests traders are preparing for a period of increased uncertainty until clearer signals emerge from the diplomatic front.