South Korea's Kospi index opened sharply lower on Monday, dropping 3% at the start of trading as markets reacted to the intensifying conflict between the United States and Iran.

The steep decline marks a significant escalation in risk-off sentiment across Asian equities, with investors moving to de-risk portfolios amid fears of broader regional instability and potential supply chain disruptions.

The Nikkei 225 index fell 1%, while the broader Topix index managed a slight gain of 0.

Japan's markets also faced downward pressure, though the reaction was more muted.

The Nikkei 225 index fell 1%, while the broader Topix index managed a slight gain of 0.43%, suggesting some divergence in sector-level resilience.

However, the overall tone across the region remained cautious, with trading volumes likely elevated as institutional investors reassessed exposure to geopolitical hotspots.

The sell-off follows a week of heightened volatility, with previous sessions already reflecting investor anxiety over stalled peace negotiations.